Table 1.

Study characteristics by study design

Study	Country	Sample size, age	Design	Intervention /control group	Duration	Intervention and cultural relevance
Non-randomized trials with or without a control group
Pande et al. [14]	India (urban)	N = 20 Age 35–58y	Case–control	Both T2D (n = 10) and healthy group (n = 10) received 1 meal/day	Acute	Provision of low-GI mixed meals using traditional Indian foods and spices in a medical setting.
Pande et al. [15]	India (urban)	N = 15 Age 42–58 y	Quasi-experimental, pre-post	Provided meals and snacks No control group	4 wk	Provision of low-GI mixed meals and snacks using traditional Indian foods and spices to cook at home.
Jain et al. [12]	India (urban)	N = 180 Mean age 47 y	Quasi-experimental, pre-post	Education No control group	3 mon	In-person education supported with a booklet describing the principles of diabetes management.
Singh et al. [16]	India (urban)	N = 120 Age 35–65 y	Quasi-experimental, pre-post	Education No-intervention control	3 mon	In-person nutrition education from dietitians. Type of PA recommended to participants not reported.
Krishnan et al. [13]	India (urban)	N = 134 Mean age 50 y	Quasi-experimental pre-post	Counselling– I – attended 1 session, no follow-up II – attended dietary counselling with periodic follow-up III – attended dietary and exercise counselling with periodic follow-up No control group	3 and 6 mon	In-person counselling to participant and caregiver/family, home visits and telephone counselling for those unable to attend in person. Type of physical activity recommended to participants not reported.
Bairy et al. [11]	India (urban)	N = 101 Median age 55 y	Quasi-experimental, pre-post	Provision of meals + education as part of an integrated naturopathy and yoga program No control group	3 mon	Meals were low-GI, plant-based, low in salt, oil, sugar. Also engaged in yoga, mild aerobic activity (walking, swimming, boat-pedalling in river), rest, “therapeutic fasting” (1–3 d) + 2 lectures/d on naturopathy, personal development + 1:1 physician counselling + 1-h cooking classes daily. Based on traditional practices. Patients were admitted to a naturopathy hospital for 15- or 30-d treatment.
Kumari et al. [17]	India (urban)	N = 202 Mean age 53 y	Quasi-experimental	Holistic lifestyle intervention Usual care controls	3, 6, and 12 mon	Interdisciplinary team provided monthly counselling for 6 mon in local language. Supported with pictures, videos, 1:1, and group sessions. Included diet, physical activity (brisk walking, yoga), tobacco cessation, stress management, self-management adherence.
St. John [18]	UK	N = 34	Quasi-experimental pre-post	Education No control group	2 mon	In-person education supported with a booklet developed for Pakistani immigrants to teach carbohydrate content of traditional foods.
Randomized controlled trials
Johansen et al. [19]	Norway	N = 198 Age 26–63 y	RCT	Education No-intervention control	7 mon	In-person, 2-h group sessions on managing blood glucose with diet and exercise (walking). Used culturally adapted resources, translated written materials, focused on traditional foods.
Raberg Kjollesdal [20]	Norway	N = 82 Age 28–62 y	RCT	Education No-intervention control	7 mon	Same as Johansen et al. [19]
Myers et al. [21]	India	N = 239 Age 25–69 y	Cluster RCT	Education and self-management support Usual care controls	6 and 12 mon	Dietitians received standardized training prior to implementation. Education provided in person by dietitian based on evidence-based nutrition practice guidelines (EBNPG) (Diabetes in India Nutrition Guidelines), motivational interviewing, goal setting, self-monitoring. Participants received handouts including meal plans, exchange lists.
Pavithran et al. [22]	India	N = 40 Age 35–65 y	RCT	Nutrition intervention Controls maintain usual diet	24 wk	Educational in-person interview focused on consuming low-GI whole grain cereals using traditional foods, periodically reinforced by a dietitian.
Pavithran et al. [23]	India	N = 80 Age 35–65 y	RCT	Nutrition intervention Controls maintain usual diet	24 wk	Educational interview focused on consuming low-GI traditional foods, periodically reinforced by a dietitian.
Yasmin et al. [24]	Bangladesh	N = 320 Age 30–85 y	RCT	Interactive voice calls and telephone-based physician access Usual care controls	6 mon	Regular personalized advice regarding diet, physical activity, medications, clinic visits. Call service provided physician contact 24/7.
Devi [25]	India (urban)	N = 340 Age 20–80 y	Pre-post, with randomization of participants	I—Education with self-learning module, paper-based II – Education with a powerpoint presentation III – usual care control group	6 mon	I—Diet and nutrition self-learning module available in Hindi and English (participant choice) + in-person 90-min discussion in the participant’s home. II – The same materials provided via laptop with an educator present, and DVD and handout for viewing independently at the participant’s home.
Islam et al. [26]	Bangladesh	N = 200 Mean age 48 y	RCT	Text messages Usual care controls	6 mon	Daily text messages (20 out of 90 related to diet) over 6 mon, guided by behavior change theory and diabetes guidelines (Bangladesh + UK and ADA).
Thadchanamoorthy et al. [27]	Sri Lanka	N = 135 Mean age 58 y	RCT	I – usual care controls II – general diabetes management education III – nutrition education	3 and 6 mon	II – Standard diet based on Dietary Guidelines and Nutrition Therapy for Specific Diseases, Sri Lanka; 4 sessions. III—Nutrition education focused on low carbohydrate diet; 4 sessions.
Varadaraj et al. [28]	India	N = 98 Age 18 + y	RCT	Education comparing 2 intensities Usual care control	3 and 6 mon	In-person nutrition education provided by a dietitian either once monthly or every 3 mon after an initial session (also provided to the usual care control).

ADA American Diabetes Association, DVD digital video disk, GI glycemic index, PA physical activity, RCT randomized controlled trial, UK United Kingdom