Effects of high-dairy versus low-dairy, high-protein and low-calorie diets combined with aerobic exercise on central body fat in overweight women: A pragmatic randomized controlled trial

Introduction

Obesity is one of the most concerning public health issues, and it is known as a predisposing factor for many chronic cardiometabolic diseases. Overweight individuals should be included in preventative interventions. Combining a high-dairy, high-Protein and low-calorie diet might help reduce appetite and body weight more effectively. We aimed to assess whether this approach, coupled with moderate-intensity aerobic activity, would be more effective in helping overweight women reduce central fat accumulation than a low-dairy diet, high in protein and low in calories.

Methods

This randomized clinical trial recruited young overweight women aged 20–45-year-old, and compared one of two 700 Kcal restricted diet management options: intervention group with a high protein with high amounts of dairy products and 40 g of casein supplement or control group with a high protein, low-dairy diet for two weeks. In addition, moderate-intensity aerobic exercise was individually determined and prescribed for both intervention and control groups. The primary outcomes were a change in abdominal and suprailiac skinfold thickness. The secondary outcomes were body weight; BMI; waist and hip circumferences measured before the trial and after two weeks. Our analysis was based on both the intention-to-treat and per-protocol principles. This trial was registered with the Tehran University of Medical Sciences (IRCT20201102049229N1).

Results

Between the 20th of January 2021 and the 18th of March 2021, 60 participants were randomly assigned to the intervention or control groups. Forty-seven of them (78%) completed the study. The mean drop in abdominal and suprailiac skinfold thicknesses was −4.82 mm and −3.22 mm, respectively, in the dairy group and −2.83 mm and −2.00, respectively, in the non-dairy group. The adjusted mean difference was −1.99 (95% CI: 0.49–3.48; p = 0.005) in abdominal skinfold thickness and −1.22 (95% CI: 0.06–2.38; p = 0.017) in suprailiac skinfold thickness in favour of the high-dairy group. All other secondary outcomes, including waist circumferences, hip circumference, Mean Body Fat, Percentage Body Fat, Soft Lean Mass, Body Mass Index, Fat Mass Index, and Fat-Free Mass Index, showed significant changes (p < 0.05) in the intervention group.

Conclusion

High-dairy, low-calorie diet is more effective than a high-protein, low-calorie diet in weight and body fat reduction, particularly central fat, in overweight young adult women.