Table 1.

Four roles of food and diet in obesity

Roles of food and diet	Strategy	Comment
Prevent weight gain (body fat gain)	Long term, population directed	Food and diet may have specific effects on metabolism or on appetite, generally for all people or for definable subgroups (personalised weight maintenance or obesity prevention diets)
Weight loss (body fat loss)	Short term,individual	Weight loss is aimed mainly at providing a vehicle to deliver the least number of calories for the longest possible time, for the greatest number of people to achieve targets. Individual preferences and cultures as well as metabolic charactistics mean that different foods and diets are preferred and more effective for some people
Prevent weight regain (body fat regain)	Long term, individual	In general, this role is likely to be similar to preventing weight gain
Optimal health for overweight/obese people during:		Nutrient content of the diet is less relevant or critical for health during short term weight loss, except for specific issues (eg, preventing gallstones by providing adequate dietary fat, postural hypotension by providing sufficient sodium and water) and for specific situations (eg, obese people with poor nutritional status preparing for surgery, where deficiencies of vitamin C or Mg might be problems)
Preventing weight gain	Long term
Weight loss	Short term
Preventing weight regain	Long term