Table 2. Summary tables.
Study | Study type | Geographical scope | Aim and main outcomes | Relevant results | |
---|---|---|---|---|---|
(a) Food price | |||||
Taxes (SSBs) | Cabrera Escobar et al.5 | Systematic review and meta-analysis of cross-sectional and longitudinal studies | USA, Brazil, Mexico and France | Aim: to evaluate the literature on SSB taxes or price increases Outcomes: consumption and demand | SSB price elasticity (9 studies): pooled own price elasticity was −1.299 (95% CI: −1.089 to −1.509). Cross-price elasticities (four studies): four articles reported cross-price elasticities, three from the USA and one from Mexico; higher prices for SSBs were associated with an increased demand for alternative beverages such as fruit juice (0.388, 95% CI: 0.009–0.767) and milk (0.129, 95% CI: −0.085 to 0.342), and a reduced demand for diet drinks (−0.423, 95% CI: −0.628 to −1.21). Higher prices for SSBs were associated with an increased demand for alternative beverages such as fruit juice and milk, and a reduced demand for diet drinks. One cross-sectional study: a 1% increase in SSB price, the point prevalence for obesity would reduce more in men (−0.34 percentage points) than in women (−0.05) One longitudinal study: found a reduction in the point prevalence of obesity (−0.03 percentage points) in adults |
Levy et al.6 | Review of RCTs and population studies | USA, UK, Belgium, Brazil, Canada and Holland | Aim: to review the literature on school nutrition policies and price interventions Outcomes: SSB consumption | Effect on kcal (two population studies): a 1% increase in the tax rate was associated with nearly 8 fewer kcal from soda consumed (P<0.05), a ~6% reduction; whereas a 20% SSB price increase was found to reduce SSB energy intake by 38.8% for adults and 48.8% for youth. Effect on consumption (review): the price elasticity for soft drinks is in the range of −0.8 to −1.0 meaning that a 10% price increase was associated with an 8% reduction in soda consumption. Effect on consumption and kcal (review): a tax increase at 20% of current prices would reduce consumption by between 16 and 20% (−36 to −45 kcal, assuming average intake of 225 kcal). Effect on obesity (two population studies): no differences were found in obesity rates between states with and without a >5% tax. A 10% increase in the price of sugar products was associated with a decrease in the prevalence of obesity by 8% | |
Welsh et al.7 | Review of modelling studies | USA | Aim and outcomes: to present recent data on SSB consumption and its health impact | Modelling study (1): the penny-per-ounce tax would reduce the consumption of SSBs by 15% among adults and prevent 95 000 coronary heart events, 8000 strokes and 26 000 premature deaths | |
Taxes (Fat) | Cash and Lacanilao8 | Review of modelling studies | Aim: to review the economic evidence of taxes Outcomes: consumption and health | Modelling study (1): the results of a possible fat tax show that an increase of 0.4–1% would not significantly affect consumption or health outcomes | |
Galizzi9 | Review of modelling studies | USA and UK | Aim: to assess the relative effectiveness of taxes Outcomes: consumption and health | Modelling study (1): a tax proportional to fat content can reduce fat intake of 1%, with a 10 times higher burden on poor consumers | |
Tiffin and Salois10 | Review | Focus on UK | Aim: to investigate the effect of nutrition policies including a fat tax Outcomes: consumption | Modelling study (1): a fat tax according to the % fat content (1.56% fat will have a tax of 1.56%), with a ceiling of 15% lead to only small changes in intakes (total fat~−1.6% saturated fat~−2.0%) | |
Taxes (fat and sugar) | Faulkner et al.11 | Scoping review of observational studies and RCTs | USA mostly with a focus on Canada | Aim: to synthesise existing evidence regarding economic policies Outcomes: obesity | Cross-sectional study (1): states without a soft drink or snack food tax were four times more likely (statistically insignificant) than states with a tax to exhibit a high relative increase in obesity prevalence |
Tax (high-energy dense foods) | Epstein et al.12 | Review of experimental research | Not mentioned | Aim: to review experimental research on policy decisions Outcomes: dietary intake and health | Experimental study (1): a 50% price increase for high-energy dense foods in a lab setting resulted in a reduction in calories of 16% |
Tax (sugar) | Powell and Chaloupka13 | Review of cross-sectional and longitudinal studies | USA | Aim: to assess the relationship between food price and weight Outcomes: obesity | Tax/price increase (one longitudinal study): a one dollar increase in the current price of sugar was associated with a 0.33 percentage point reduction in the probability of obesity |
Subsidies (fruit and vegetables) | Black et al.14 | Systematic review of RCTs, CBAs and ITS studies | USA, UK and New Zealand | Aim: to determine the impact of the food subsidy programs Outcomes: fruit and vegetable intake | RCT (1): overweight women who received $10 per week of F&V for 6 months increased mean consumption of fruit by 1.0 serves per day (95% CI: 0.1–1.9, P=0.02) and vegetables by 0.9 serves per day (95% CI: 0.3–1.5, P=0.002) whereas the intake of controls was unchanged |
An15 | Review of RCTs, cohort and pre–post-test studies | USA, Germany, UK, Canada, South Africa, France and Holland | Aim: to review the effectiveness of monetary subsidies Outcomes: consumption | Cohort study (1): a 10 and 25% discounts on healthier foods were associated with an increase in daily F/V intake by 0.38 and 0.64 servings, respectively. Before and after study(1): preliminary evidence shows that the demands for fruits are price elastic— a 1% decrease in price is associated with a larger than 1% increase in quantity demanded. RCT (1): when the price in hospital cafeterias was lowered on healthy foods by 15–25%, fruit intake increased by about 30%. | |
Price elasticities | Andreyeva et al.16 | Systematic review of ITS, household surveys and retail scanner data | USA | Aim: to assess mean elasticities by food category Outcomes: consumption | Based on 160 studies: the mean price elasticity for the soft drink category (0.79, absolute value) is based on 14 estimates, with a range of 0.13–3.18 and was considered to be most elastic followed by juice, fruit, sugar and sweets, fats and oils. A 10% increase in soft drink prices should reduce consumption by 8–10% |
Maniadakis et al.17 | Systematic review of longitudinal, modelling, cohort, demand and cross-sectional studies | USA, Norway and Singapore | Aim: to assess the effect of taxation Outcomes: consumption and caloric intake | Demand studies (12): the price elasticity of demand for beverages is in the range of −0.5 to −1.6, depending on the beverage. The caloric effect of a 10% increase in prices reduces energy intake by a max of 50 calories per day, which is not considered significant. Longitudinal studies (2): the price elasticity of demand for beverages and foods is in the range of −0.05 to −0.35 depending on the beverage and food considered | |
Powell et al.18 | Systematic review of modelling studies using time series or longitudinal data | USA | Aim: to assess the price elasticity of demand for SSBs and fruits and vegetables Outcomes: SSB and fruit and vegetable consumption | SSBs (14): mean price elasticity estimate of −1.21 implies that a tax on SSBs of 20% would reduce overall consumption by 24%. Fruit and vegetables (6): the mean price elasticity was −0.49 and −0.48, respectively, suggesting that subsidising fruits and vegetables by 20% would increase consumption by 10% | |
Taxes and subsidies | Eyles et al.19 | Systematic review of simulation studies | The 34 member countries of the OECD | Aims: to investigate the estimated association between food pricing and intake or health outcomes Outcomes: food intakes | Carbonated soft drinks (4): the estimated mean own-PE, which represents the change in demand with a 1% change in price, for carbonated soft drinks was −0.93 (range,−0.06, −2.43) Saturated fat (3): for a flat rate tax, the mean modelled reduction in saturated fat intake in response to a 1% increase in price was −0.02% energy from saturated fat Fruit and vegetables (3): the estimated own-PE was −0.35. After sensitivity analysis the own-PE is −0.54 |
Mozaffarian et al.20 | Systematic review and grading of evidence | USA and UK | Aim: to identify and assess the evidence for the effectiveness of population interventions Outcomes: consumption and health | Tax on SSBs (review): a 10% increase in the price of SSBs would decrease consumption by 8–10%. Fruit and vegetable subsidy (modelling; 1): a 10% price subsidy would lead low-income US consumers to increase their intake of both F/V by 2–5%. A subsidy of $10 per week in vouchers to purchase F/V for 6 months led to a significantly higher intake in intervention groups compared with the control group (7.8 vs 4.8 servings per day). Six additional months after the intervention ended, this increase was sustained (7.5 vs 4.9 servings per day). Taxes and subsidies (modelling;1): the combination of taxing less healthy foods and using this revenue ($580 million) to subsidise the price of fruits and vegetable would sufficiently alter consumption to prevent 6000 deaths attributable to CVD and cancer each year | |
Thow et al.21 | Systematic review of empirical and modelling studies | USA | Aim: to assess the effect of food taxes and subsidies Outcomes: diet and health status | Tax on salty snack (modelling; 1)s: a 20% tax would reduce consumption by 115–170 g per person per year, equivalent to ~830 calories. Fruit and vegetable subsidy (modelling; 1): a subsidy that would lead to a lasting price reduction of 1% would prevent 6733 cases of CHD and 2946 cases of ischaemic stroke | |
Thow et al.22 | Systematic review of modelling studies and two RCTs | USA, France, Holland, UK, Brazil, Finland, Sweden, Norway, New Zealand and Australia | Aim: to assess the effect of food taxes and subsidies Outcomes: fruit and vegetable, total calories, SSB, fat, sugar and sodium consumption | Subsidies: a RCT found that a subsidy of 12.5% on healthy food had no effect on consumption. Another RCT stated that a subsidy of 50% on F/V would increase consumption by 25%. Subsidies modelling: four studies stated a subsidy of 10% on F/V increases consumption by ~5%, with one study estimating a 1.5% increase in consumption in response to a 1.8% price decrease. Three modelling studies found that subsidies paired with taxes (range 10–20%) could reduce total calories by ~1%. Tax on SSBs: 16 studies modelled the effect of a 5–30% SSB tax and showed a reduction in consumption (5–48%) demonstrating that consumption was proportional to the taxes applied. Substitution effects modelling: four studies modelled substitution between beverages in response to a 5–20% tax and suggested that consumers would reduce caloric intake of SSBs, by 10–48% in adults and by 5–8% in children and increase consumption of other beverages such as milk, low-calorie beverages, tea and coffee. One study suggested that a focus on a single nutrient may increase intakes of other unhealthy nutrients. Fat tax modelling: four studies showed that relatively small taxes on fat (5–17.5% $0.005 per g) can reduce fat and/or saturated fat consumption by 0–3%, reduce consumption of certain high-fat foods, and induce substitution with lower-fat options. Sugar subsidy modelling (1): an implicit sugar subsidy would result in a price decrease of 36% and an increase in consumption (7.5%). Sodium tax modelling (1): a sodium tax that increased the price of salty foods by 40% would reduce sodium consumption by 6%. Taxes based on nutrient profiling (8): taxes on ‘unhealthy'/‘high calorie' foods ranged from 10–50% and reduced consumption by 6.5–8%. A 25% tax on ‘red' labelled foods significantly reduced consumption among obese participants (40%) and reduced consumption among non-obese participants by 10%. | |
Capacci et al.23 | Review of simulation studies | USA, Denmark, UK, France and Sweden | Aim: to provide a classification of public policies to promote healthy eating and mapping of existing measures in Europe Outcomes: saturated fat intake and cases of CHD and ischaemic strokes | Subsidies modelling (1): a 1% decrease in the price of all fruits and vegetables could translate into a mean decrease of around 6700 cases of CHD and almost 3000 ischaemic strokes. Saturated fat modelling (1): a tax of 14 DDK per kg of saturated fat using Danish data is estimated to reduce saturated fat intake by 7.4%. A tax on saturated fat would cause a small rise in salt intake as a result of cross-price elasticity effects and might overall result in more deaths than it averts. In addition, the saturated fat tax also results in a decrease in F/V consumption of ~2–4% | |
Shultz et al.24 | Systematic review | USA | Aim: to assess the effects of the 2009 food package revisions on healthy food and beverage availability, breastfeeding outcomes, and dietary intake of WIC programme participants 5 years later using only peer-reviewed research Outcomes: fruit intake | Significant changes were observed in dietary intake in another study, with increased fruit consumption by 0.33 servings per day among Hispanic mothers enrolled in WIC | |
(b) Food promotion | |||||
Marketing/advertising to children | Gregori et al.25 | Systematic review of RCTs | UK and USA | Aim: to perform a SR aimed at assessing the effect of TV advertising Outcomes: nutrition intake | 4 RCTs: showed that total kcal intake was significantly higher and considerable more snacks were consumed after exposure to FA than after the NA. One RTC showed that the obese and overweight groups ate significantly more than the healthy weight group, both with FA and with NA |
Boyland and Halford26 | Review | UK | Aim: to study the effect of TV advertising and branding on food preference and eating behaviour Outcomes: food intake | Two cross-sectional experimental studies found that exposure to food advertising increased food and calorie intake in all children. The obese and overweight groups ate significantly more than the healthy weight group, both with FA; and with NA | |
Hingle and Kunkel27 | Review | US focused | Aim: to analyze the role of food marketing and to evaluate intervention efforts to reduce exposure to advertising messages for unhealthy food products Outcomes: food consumption and obesity | The IOM report concluded that there is strong evidence that advertising influences the short-term food consumption of children aged 2–11 years; moderate evidence that it influences the regular diet of children aged 2–5 years; and weak evidence that it influences children aged 6–11 years. Economics study (1): estimates that the impact of banning food advertisements on television would reduce the baseline rate of childhood obesity in the USA from 17% to somewhere in the range of 10.5–14.5% | |
Nutrition education | Mytton et al.28 | Systematic review and meta-analysis of RCTs | Europe, North America and India | Aim: to study the effects of either an increased or no increase in fruit and vegetable intake Outcomes: energy and fruit and vegetable intake | RCTs (8): No significant differences (P=0.93) were found in change in energy intake among studies supporting a general increase in F/V consumption (193 kJ) and studies providing a specific fruit portion per day (768 kJ). Two RCTs found that the difference in F/V intake between the arms (dietary advice vs no advice) were 294 g and 5.7 portions, with a follow-up duration of 4 and 52 weeks, respectively |
Harris et al.29 | Systematic review of RCTs | USA, The Netherlands and Belgium | Aim: to assess the effectiveness of adaptive e-learning for improving dietary behaviours Outcomes: fruit and vegetable, total fat, saturated fat, total energy from fat, dietary fibre and daily energy intake | When studies reporting the same outcomes were pooled in a random effects meta-analysis, e-learning interventions were associated with a WMD of 0.24 servings (95% CI: 0.04 servings to 0.44 servings; P=0.019) of F/V per day(22 RCTs); WMD of –0.78 g (95% CI: –2.5 to 0.95 g) of total fat consumed (22 RCTs); WMD –0.24 g (95% CI: –1.44 to 0.96 g; P=0.7) of saturated fat intake (8 RCTs); WMD of –1.4% (95% CI: –2.5 to –0.3% P=0.012) of total energy consumed from fat; WMD of 4 kcal (95% CI: –85 to 93 kcal; P=0.93) of daily energy intake | |
Thomson and Ravia30 | Systematic review of clinical trials and RCTs | USA | Aim: to identify intervention trials designed to promote F/V intake Outcomes: fruit and vegetable intake | (RCTs): different nutrition education interventions were investigated and the effect on F/V. This review found increases in F/V intake that ranged from 0.4 to 1.4 servings per day | |
Levy et al.6 | Review | Mostly USA | Aim: to review the literature on school nutrition policies and price interventions Outcomes: SSB consumption | Two cross-sectional studies found no relationship to SSB consumption for nutrition education programs. RCT: SSB consumption over 3 days decreased by 0.6 servings in the intervention group receiving an ES curriculum compared with 0.2 servings in the control group. RCT: an education program aimed at discouraging SSB found that daily consumption of SSB decreased in the intervention group by ~20%, with almost no change in the control group | |
Campaigns | Rekhy and McConchie31 | Review | Australia, USA, Denmark, UK and New Zealand | Aim: to examine the effect of campaigns and interventions Outcomes: fruit and vegetable intake | Australian ‘Go for 2&5' campaign: analysis after 3 years showed that there was an average net increase of 0.8 serves per day (11.4%) for overall consumption of fruits (+0.2; 10%) and vegetables (+0.6; 12%). Modest impact on consumption behaviour in the long run. U.S. '5 A Day for Better Health' programme and ‘'Fruits & Veggies – More Matters': survey results between 2004 and 2009 have shown that although F/V consumption for adults remained unchanged at 1.81 cups per person per day, it did increase for children <6 years old (7%) and between 6 and 12 years old (5%). Danish ‘6 a day' campaign: between ‘95 and ‘04, the survey reported that F/V consumption for the 4- to 10-year-old and 11- to 75-year-old group increased by 29%, 58%, 41% and 75%, respectively. For the period ‘03–‘08, the average intake of vegetables for adults (18–75 years old) was reported to be 162 g per person per day, whereas the average intake of fruit was 283 g per person per day. This equals 445 g per day, exceeding the minimum WHO requirements of 400 g per day, demonstrating the success of the Danish campaign U.K.'s ‘Food Dudes' programme: there is a 60–200% increase in F/V consumption and where monitored, an associated decline in consumption of unhealthy foods by 20–100%. New Zealand's ‘5+A Day' Programme: between '95 and '12 there was a reported increase of 23% in F/V intake of 5+ servings per day. In 2011, 60.4% of the population was reported to be consuming the recommended two serves of fruit daily and 66% of the population was consuming the recommended three serves of vegetables a day |
Snyder32 | Review | Developing and developed countries | Aim: to review the evidence for the effectiveness of health communication campaigns to inform future nutrition campaign Outcomes: effect size, fruit and vegetable intake | Preliminary analysis of 37 F/V media campaigns found an average campaign effect size of r=0.08. Other SRs of F/V interventions found increases in F/V servings and decreasing fat per calories consumed. In-school nutritional campaigns aimed at fourth and fifth graders found an average effect of r=0.12 | |
Perez-Cueto et al.33 | Review of policy documents | 17 EU member states | Aim: to identify and assess healthy eating policies at national level Outcomes: food consumption and health | Nutrition education programs: the Portuguese PPC comprises training sessions for the adult population and reported reductions in total energy intake (−6.3%), cholesterol (−9.2%), total fat (−12.2%) and saturated fat (−15.6%) between baseline and follow-up. Public information campaigns: the Italian ‘Eat well, live healthy' campaign reported that 37.8% of the participants improved their dietary habits as a consequence of the campaign. The UK's ‘five-a-day' campaign showed that only 24% of surveyed individuals reported an increased F/V intake in the previous 6 weeks | |
(c) Food provision | |||||
Workplace (fruit and vegetable and fat) | Mhurchu et al.34 | Systematic review of RCTs | USA, Belgium and Holland | Aim: to assess the effect of worksite interventions Outcomes: intake | Fruit and vegetable intake: two RCTs showed that combined average daily intake of fruit and vegetable increased from +3 to +16% in intervention groups, compared with −2 to +4% in the control groups. Total fat intake: five RCTs showed that average daily intake of total fat as a percent of energy decreased from −2.2 to −9.1% in intervention groups compared with +1.3 to −1.8% in the control groups |
Montano et al.35 | Review—meta-analysis of RCTs | Not mentioned | Aim: to assess the types of SEP in RCTs and estimate the moderation of SEP in workplace intervention Outcomes: fruit and vegetable intake | 36 RCTs: daily consumption of fruit and vegetables increased significantly (SMD 0.12, 95% CI: 0.01–0.22). There were no statistical significant differences between occupational classes and fruit and vegetable intake (SMD 0.117, 95% CI: −0.049 to 0.282, EM 0.000, 95% CI: −0.230 to 0.231) | |
Thompson and Ravia30 | Systematic review of clinical trials and RCTs | USA | Aim: to identify intervention trials designed to promote F/V intake Outcomes: fruit and vegetable intake | RCTs: results for seven different work-based interventions reported that increase in daily F/V servings ranged from 0 to 1.52 servings per day and averaged 0.8 servings a day | |
Schools (SSBs) | Levy et al.6 | Review | Mostly USA | Aim: to review the literature on school nutrition policies and price interventions Outcomes: SSB consumption | Eliminating access: was predicted to reduce SSB consumption by 4% (longitudinal study). Another cross-sectional study found that eliminating access would lead to 0.16 fewer servings per day. Removing SSBs from cafeteria vending machines led to a 35% decline in SSB consumption, but they were obtained from non-cafeteria vending machines and home (time series). Another time-series study also found an increase of SSB consumption at home |
Patel and Cabana36 | Review | USA, Germany and UK | Aim: to summarise school-based interventions and policies Outcomes: beverage intake | Cross-sectional (1): replacing SSBs with water is estimated to result in an average reduction of 235 kcal per day among 2–19 years old. Two European studies associated school drinking water provision and promotion with an increase in student water consumption, but no change in student SSB intake | |
Schools (fruit and vegetables) | Evans et al.37 | Systematic review and meta-analysis | UK, USA, The Netherlands, New Zealand, Norway, Canada and Denmark | Aim: to quantify the impact of school-based interventions on fruit and vegetable intake in children aged 5–12 years Outcomes: fruit and vegetable intake | Fruit and vegetables: the results of the meta-analyses indicated an improvement of 0.25 portions (95% CI: 0.06, 0.43 portions) of fruit and vegetable daily intake if fruit juice was excluded and an improvement of 0.32 portions (95% CI: 0.14, 0.50 portions) if fruit juice was included. Improvement was mainly due to increases in fruit consumption but not in vegetable consumption. The results of the meta-analyses for fruit (excluding juice) and vegetables separately indicated an improvement of 0.24 portions (95% CI: 0.05, 0.43 portions) and 0.07 portions (95% CI: 20.03, 0.16 portions), respectively |
Schools (fat and fruit and vegetables) | Jaime and Lock38 | Systematic review of RCTs, non-RCTs and cross-sectional studies | USA and Europe | Aim: to review the effectiveness of school food and nutrition policies worldwide Outcomes: fat and fruit and vegetable intake | Fat intake (3): all guideline interventions targeting fat intake led to significant decreases in total fat (range −2.0 to −10.9% of energy) and saturated fat intakes (range −0.9 to −5.2% of energy) (1 RCT and 2 non-randomised not controlled trials) Fruit and vegetable intake: two RCTs targeting F/V intake led to significant increase from +0.30 to +0.37 servings per day. Providing a free piece of fruit per d resulted in an increase in F/V intake between +0.38 to +0.44 servings per day (cluster RCT). Furthermore, intake increased 117 g per d for the intervention group vs 67 g per d for the control group (cross-sectional) Effect in fruit intake: increase across reception and year 1 pupils of 0.4 portion (95% CI: 0.2–0.5) and 0.6 portion (95% CI: 0.4–0.9) at 3 months, which fell to 0.2 portion (95% CI: 0.1–0.4) and 0.3 portion (95% CI: 0.1–0.6) at 7 months, respectively (non-randomised non controlled trial) |
Delgado- Noguera et al.39 | Systematic review and meta-analysis of RCTs and CCTs | USA, UK, the Netherlands, Ireland and Italy | Aim: to assess the effectiveness of school interventions Outcomes: fruit and vegetable consumption | Price interventions: providing subsidised F/V in schools led to an increase in consumption of +0.59 servings per day. Another study established a subsidised fruit tuck shop for 1 year in intervention schools, but the consumption of F/V did not increase. A pooled analysis of these two RCTs found no significant differences between intervention and control group (SMD 0.02, 95% CI: −0.08, 0.12; I2=0%). A CCT investigated giving each student one piece of F/V daily for 2 years. With this intervention, fruit intake increased by +0.2 servings after 3 months, but the effect dropped back to +0.1 servings at 7 months, and returned to baseline in the second year. Computer-based interventions: a CCT found significant increases in F/V consumption in the intervention schools, whereas two RCTs also found increased consumption. Pooled analysis of the two RCTs did find significant differences between the intervention and control groups (SMD 0.33, 95% CI: 0.16, 0.50; I2=0%) | |
Stables et al.40 | Review of pre–post-test studies | USA | Aim: to profile the 5-day interventions Outcomes: fruit and vegetable intake | Pre-test–post-test: four of the seven projects reported significant changes in vegetable and fruit consumption, ranging from a 0.2 to 0.7 serving net change between treatment and control groups | |
Perez-Cueto et al.33 | Review of policy documents | 17 EU member states | Aim: to identify and assess healthy eating policies at national level Outcomes: fruit and vegetable intake | School (1): fruit consumption as a morning snack among children at MS increased (6.5% after vs 3.6% before). Fruit consumption in general also increased among adolescents (17% after vs 4% before), whereas SSB consumption decreased (3.3% after vs 9.6% before). Workplace (1): the Danish ‘six-a-day' intervention provided a free fruit to their employees between 2001 and 2003 daily fruit consumption increased by 3.42 units on average | |
Schools (salt) | Weichselbaum and Buttriss41 | Review | UK | Aim: to review current dietary and lifestyle habits of school-aged children in the UK and considers the impacts of these habits Outcomes: sodium intake | Limit range of unhealthy products and provide healthier options: a mixed methods study with a repeat cross-sectional design found that healthier school lunches not only improved nutrient intake at lunch time, but that these were also associated with improvements in the overall diet of children aged 4–7 years. Sodium intakes decreased significantly between 2003/2004 and 2008/2009, from 2.0 g to 1.85 g per day. In 11–12 year olds there was a significant decrease in intake of sodium from 2.59 to 2.15 g per day |
(d) Food composition | |||||
Reformulation (trans fat) | Downs et al.42 | Systematic review of ITS, post-test, pre–post-test and case–control studies | Denmark and the Netherlands | Aim: to systematically review evidence for the effectiveness of policies aimed at reducing industrially produced TFAs in food Outcomes: consumption | Voluntary reformulation: of TFA levels in the Netherlands were associated with a 20% reduction in dietary intake. Pre–post-test (1): energy intake in the form of TFAs decreased from 1.0% before reformulation to 0.8% after. TFA intake from fats was the same. Denmark's trans fat ban (pre–post-test): TFA intake decreased from 4.5 g per day in 1976 to 1.5 g per day in 1995 and TFAs were virtually eliminated from food in 2005 after the ban |
Mozaffarian and Clarke43 | Meta-analysis of RCTs and prospective cohort studies | North America and Europe | Aim: to evaluate the effect of reduced trans fatty acid by means of reformulation Outcomes: consumption and CHD | RCTs (13): for PHVO with 20% TFA, replacement with soybean, canola or high oleic sunflower oils would produce the largest (8.8–9.9%) CHD risk reductions. For PHVO with 35% TFA, risk reductions for replacement fats and oils ranged from 11.9 to 16.0%, with vegetable oils producing the largest decline. Predicted risk reductions were greatest for replacement of PHVO with 45% TFA, including risk reductions of 18.7 (soybean) and 19.8% (canola oil). Prospective cohort studies (4): for PHVO with 20% TFA, replacement with cottonseed, soybean or canola oils would produce the largest reductions (19.0–21.8%) in CHD risk. For PHVO with 35% TFA, risk reductions for replacement fats and oils ranged from 14.4 to 33.4%, with vegetable oils producing the largest decline. Predicted risk reductions were greatest for replacement of PHVO with 45% TFA, including risk reductions of 39.6 (soybean) and 38.6% (canola oil). In prospective cohort studies, each 2% energy replacement of TFAs with SFAs, MUFAs or PUFAs would lower CHD risk by 17% (95% CI: 7–25%), 21% (95% CI: 12–30%) or 24% (95% CI: 15–33%), respectively | |
Reformulation | Livingstone et al.44 | Review | Focus on UK | Aim: to examine the effects of milk and dairy products that have been modified through alteration of the dairy cow's diet Outcomes: absolute CHD and stroke risk. Cardiovascular events | One double-blinded, randomised, cross-over, intervention study modified the fat content through feeding and found that the SFA content was reduced by 16.1% and the MUFA and PUFA content was increased by 9.9% and 7.5%, respectively. The reductions in LDL levels would be equivalent to a reduction in absolute risk of CHD and stroke of 7% and 5%, respectively. A SR and meta-analysis of RCTs suggested that replacement of 9.9% of dietary energy from SFA with PUFA resulted in an overall pooled risk reduction of 19% (relative risk 0.81; 95% CI: 0.70, 0.95; P ¼ 0.008) |
(e) Food labelling | |||||
Menu labelling | Sinclair et al.45 | Systematic review and meta-analysis of experimental and quasi-experimental studies | Aim: to determine whether the provision of menu-based nutrition information affects the selection and consumption of calories in restaurants and other foodservice establishments Outcomes: consumption | Menu labelling with calories alone did not have the intended effect on decreasing calories selected and consumed compared with the control group (−31 kcal (P=0.35) and −13 kcal (P=0.61), respectively) (pooled mean difference). Conversely, when conditions that provided additional contextual or interpretive information were examined, the pooled mean difference in calories selected was 67 fewer calories (95% CI: −116.99 to −17.79; P=0.008). Contextual or interpretive interventions resulted in a pooled mean difference in calories consumed of 81 fewer calories (95% CI: −138.99 to −22.36; P=0.007) | |
Swartz et al.46 | Systematic review of experimental and quasi-experimental studies | USA | Aim: to evaluate the effect of calorie labelling on food choice Outcomes: consumption | 2 non-blind RCTs: Overall, participants did not differ significantly in the number of calories they consumed by menu type (no label 739, calorie labels 805, no value pricing 761 calories) (no label 1459 vs label 1335 vs calorie+information 1256). However, combining the two label menus vs the no label menu showed that the labelled condition consumed fewer calories (label 1286 vs no label 1466) | |
Nutrition labelling | Campos et al.47 | Systematic review of cross-sectional, experimental, natural experiment and longitudinal studies | USA, Europe, Canada, Trinidad, Australia, New Zealand, UK and Thailand | Aim: to review research on consumer use and understanding of nutrition labels, as well as the impact of labelling on dietary habits Outcomes: fat consumption | Observational studies: several studies have reported an association between label use and lower-fat consumption, and reported that people are more likely to eat healthier varieties of foods. Experimental studies: participants tended to consume greater amounts of reduced energy food in terms of weight, however total energy intake was significantly lower |
Downs et al.42 | Systematic review | Canada and USA | Aim: to review evidence for the effectiveness of policies aimed at reducing industrially produced TFAs in food | 2 pre–post-tests: after mandatory labelling led to 76% of foods meeting voluntary TFA limits, intake in the population still exceeded the WHO recommendation that <1% of dietary energy intake should come from consuming TFAs. Blood: mean TFA level decreased from 43.7μmol l−1 in 2000 to 19.4 μmol l−1 in 2009 (that is, 58% decrease) | |
Finkelstein et al.48 | Review of experimental studies | England, USA | Aim: to present and discuss seven proposed intervention strategies to promote healthy eating Outcomes: energy and fat intake | Nutrition labelling: a lab-based study providing nutrition information on labels during meals had no impact on energy intake. Similarly, a controlled experiment in a restaurant setting found that provision of nutrition information had no effect on overall energy and fat intake | |
Hawley et al.49 | Review | the Netherlands | Aim: to review the literature on front-of-pack labelling and supermarket shelf-labelling system Outcomes: consumption | Cross-sectional lab-based design: one study researched the effect of the choices logo on chocolate mousse cake to address the ‘health halo' concern and found that the cake was perceived as ‘less unhealthy', but there was no difference in taste perception or cake consumption compared with not having the logo. This suggests that the logo does not promote overconsumption. | |
Vyth et al.50 | Review of modelling studies | European countries, UK, Australia, New Zealand, USA, Canada | Aim: to evaluate the methodological quality of current front-of-pack labelling research and discuss future research challenges Outcomes: intake and health | Modelling studies: replacing typical daily menus and foods by choices menus and choices compliant foods can potentially lead to improved nutrient intakes towards recommendations | |
(f) Food supply chain, trade and investment | |||||
Trade and market liberalisation | Friel et al.51 | Review | Pacific Island countries, Central and North America | Aim: to review the available evidence on the links between trade agreements, food environments and diets from an obesity and NCD perspective Outcomes: soft drink consumption, NCD risk | Economic modelling study: demonstrated that liberalisation of FDI through trade agreements with the USA significantly increased the amount of soft drinks consumed within signatory LMICs, and consequently increased the risk of NCDs, particularly diabetes. Of key concern in the Pacific region has been the increasing import of fatty products and the, therefore, rising saturated fat intakes. For example, between 1963 and 2000, total fat supply increased by 80% in some Pacific Island countries |
Traill et al.52 | Review | High, high–middle, middle–low and low-income countries | Aim: to describe and discuss the dietary and nutritional changes that have occurred since the 1992 International Conference on Nutrition by attempting to untangle the multitude of factors that have contributed to such changes | Overall, evidence indicates the price-induced impact of trade liberalisation on consumption and diets has been modest. The World Bank has estimated that even complete trade liberalisation would raise prices of agricultural commodities by only 5.5%, and, thus, such results as the URAA's achievement of only partial liberalisation are unlikely to have resulted in significant dietary change. The share of processed food in food and agricultural exports grew from 54 to 69% for high-income countries and from 49 to 67% for Asia between the 1970 s and 2000 s. Although models indicate relatively minor price changes for agricultural commodities, trade liberalisation may have induced other, less quantifiable changes in food supply systems. In India, market liberalisation in the mid-1990 s stimulated a rapid increase in imports of low-priced vegetable oils, which corresponded with a simultaneous increase in consumption | |
Monetary subsidies and taxes | Thow et al.21 | Systematic review of empirical and modelling studies | USA, UK, Sweden, Denmark, Norway, Egypt, France, Ireland and Scotland | Aim: to assess the effect of food taxes and subsidies Outcomes: diet and health status | Modelling study (1): seven scenarios for taxing unhealthy and subsidising healthy foods and nutrients in Denmark were examinated. Each involved the equivalent of halving VAT on F/V. It was concluded that subsidising specific nutrients was more effective than subsidising food groups. Their best revenue-neutral scenario decreased average consumption of sugar by 6.5%, fat by 2.5% and saturated fat by 3.6%. Modelling study (1): it was predicted that increasing soft drink prices in Norway by 27% would reduce average consumption in heavy (44%) and light soft drink consumers (17%). One study modelled extending the VAT at 17.5% in the UK and Northern Ireland to food products that were the main sources of saturated fat. They calculated that saturated fat consumption would reduce deaths from ischaemic heart disease by 1.8–2.6%, or 1800–2500 deaths per year in the country |
Galizzi9 | Review of modelling studies | USA and UK | Aim: to assess the relative effectiveness of taxes Outcomes: ischaemic risks | Modelling study (1): an increase in VAT up to 17.5% on fat foods in the USA can reduce ischaemic risks of 1.8–2.6% with more a 1000 lives saved a year | |
Climate change | Lake et al.53 | Review | Developed countries (using the UK as a case study) | Aim: to investigate the potential impact of climate change on food security Outcomes: human health and obesity | The likely impact of climate change on world food prices: rises in food price associated with climate change may reduce the nutritional quality of dietary intakes because individuals may shift to lower-cost food items (less healthy choices) and can lower the nutritional status of some groups. It can also increase the risk of obesity, particularly among children, young adults, smokers, lower-income groups and frail older people. |
(g) Multi-component interventions | |||||
Food promotion and provision | Blanchette and Brug54 | Review | USA, Norway, Denmark and UK | Aim: to review the current literature on interventions to increase the consumption of fruits and vegetables among children Outcomes: fruit and vegetable intake | The results of the interventions showed daily increases in F/V intake from 0 to 2.54 daily servings, with 14 of the 15 interventions resulting in increased consumption of fruit and/or vegetables. Increases in fruit intake were more frequent and substantial than increases in vegetable intake |
Patel and Cabana36 | Review | USA, Germany and UK | Aim: to summarise school-based interventions and policies Outcomes: beverage intake | Replacing SSBs with water: two RCT studies associated school drinking water provision and promotion with an increase in water consumption, but no change in SSB intake | |
Epstein et al.12 | Review of experimental research | Not mentioned | Aim: to review experimental research on policy decisions Outcomes: dietary intake and health | Experimental study (1): A 20% subsidy on healthy food, together with educational materials and blood pressure readings led to a 6% increase in consumption of healthy foods and a 2% reduction of unhealthy foods. Consumption of healthy foods increased by 17% at follow-up with maintenance of the 2% decrease in unhealthy food consumption | |
Labelling and voluntary reformulation (trans fat) | Downs et al.42 | Systematic review of ITS, post-test, pre–post-test and case–control studies | Canada | Aim: to review evidence for the effectiveness of policies aimed at reducing industrially produced TFAs in food Outcomes: dietary intake | Interrupted time series (1): mandatory TFA labelling combined with voluntary limits was associated with a 30% reduction in dietary intake in the general population. TFA intake: mean TFA intake decreased from 8.4 g per day in the mid-1990 s to 3.4 g per day in 2008, which is still above WHO recommendations. On average, there was a 30% decrease in TFA intake between 2004 and 2008. SFA intake did not increase during this period |
Abbreviations: CBA, Controlled Before- and After studies; CCTs, Controlled Clinical Trials; CHD, Coronary Heart Disease; CVD, Cardiovascular Disease; ES, Elementary School; EU, European Union; FA, food advertisements; FDI, Foreign direct investment; IOM, Institute of Medicine; ITS, Interrupted Time Series; LDL, low-density lipoprotein; LMICs, Low and middle income countries; MS, Middle school; MUFA, monounsaturated fatty acids; NA, non-food advertisements; NCD, non-communicable disease; PE, Price Elasticity; PHVO, partially hydrogenated; PPC, Portuguese 'Peso Comunitario' vegetable oils; PUFA, polyunsaturated fatty acids; RCT, randomised controlled trials; SEP, Socioeconomic Positions; SFA, saturated fatty acids; SMD, Standardised Mean Difference; SR, systematic reviews; SSB, sugar-sweetened beverages; TFA, trans fatty acids; URAA: Uruguay Round Agreement on Agriculture; VAT, value-added tax; WHO, World Health Organisation; WMD, weighted mean difference.