The Effect of a Vegetarian vs Conventional Hypocaloric Diabetic Diet on Thigh Adipose Tissue Distribution in Subjects with Type 2 Diabetes: A Randomized Study

ABSTRACT

Objective: The aim of our study was to compare the effects of a vegetarian and a conventional diet on thigh adipose tissue distribution in subjects with type 2 diabetes (T2D).

Methods: Seventy-four subjects with T2D were randomly assigned to either follow a vegetarian diet (V, n = 37) or a control group who followed an isocaloric conventional anti-diabetic diet (C, n = 37). Both diets were calorie restricted (−500 kcal/day). To measure insulin sensitivity, the hyperinsulinemic (1 mU.kg⁻¹.min⁻¹) isoglycemic clamp was conducted. β-Cell function was assessed using a mathematical model after a test meal. Magnetic resonance imaging of the thigh was performed. All subjects were examined at 0, 3, and 6 months. Statistical analyses were performed using repeated measures analysis of variance and a multivariate regression model.

Results: Greater reduction was observed in total leg area in V (−13.6 cm² [95% confidence interval [CI], −14.2 to −12.9] in V vs −9.9 cm² [95% CI, −10.6 to −9.2] in C; Gxt p < 0.001). The reduction in subcutaneous fat was comparable in response to both diets (Gxt, p = 0.64). Subfascial fat was reduced only in response to a vegetarian diet (−0.82 [95% CI, −1.13 to −0.55] cm² in V vs −0.44 [95% CI, −0.78 to +0.02] cm² in C; Gxt, p = 0.04). The reduction in intramuscular fat tended to be greater in response to a vegetarian diet (−1.78 [95% CI, −2.26 to −1.27] cm² in V vs −0.57 [95% CI, −1.06 to −0.09] cm² in C; Gxt, p = 0.12). Changes in subcutaneous and subfascial fat correlated with changes in glycated hemoglobin (HbA1c), fasting plasma glucose, and β-cell insulin sensitivity. After adjustment for changes in body mass index (BMI), correlations remained significant for changes in fasting plasma glucose and β-cell insulin sensitivity and with changes in triglycerides.

Conclusions: Our data indicate the importance of both subcutaneous and subfascial fat in relationship to glucose and lipid metabolism.

Abbreviations: BMI , body mass index; C , control group; FPG , fasting plasma glucose; Gxt , interaction between group and time; HbA1c , glycated hemoglobin; MCR , metabolic clearance rate of glucose; OPLS , orthogonal projections to latent structure; T2D , type 2 diabetes; V , vegetarian group

KEYWORDS:

• Insulin sensitivity
• thigh adipose tissue
• intramuscular fat
• type 2 diabetes
• vegetarian diet

Acknowledgment

We thank Monika Kolarova for routine magnetic resonance image processing.

Funding

This work was supported by the project grant AZV15-27338A.

Author contributions

H.K. and T.P. designed the study, wrote the grant application, recruited the participants, collected the data, and wrote the article. M.K., V.H., A.S., S.H., and A.M. were involved in acquisition and analyses of data. M.H. carried out the statistical analyses and interpretation of data. All authors had full access to the data and revised and approved the article for publication. The guarantor is T.P.