Background:
Weight loss resulting from a low-calorie diet (LCD) is an effective strategy to improve risk factors for cardiometabolic diseases. However, sexual dimorphism may be present in LCD-induced body weight loss and improvements in cardiometabolic risk factors, and maintenance of changes during follow-up.

Design:
782 overweight or obese participants (35% men) were included in the large-scale multicenter DiOGenes trial (ClinicalTrials.gov Identifier: NCT00390637). Participants followed an 8-week LCD (~800 kcal/day), with a 6-month follow-up weight maintenance period on ad libitum diets varying in protein content and glycemic index. Body weight and several cardiometabolic risk factors were determined. A mixed-model analyses was performed with adjustment for age, weight (loss and regain) and (change in) baseline value and diet.

Results:
Men lost more body weight during the LCD period (-12.8 ±3.9 vs. -10.1 ±2.8kg, respectively, p<0.001), but regained more weight during the follow-up period than women (1.5 ±5.4 vs. -0.5 ±5.5kg, respectively, p<0.001). Although beneficial LCD-induced changes in cardiometabolic risk factors were found for both sexes, improvements in HOMA-IR, muscle and hepatic insulin sensitivity, triacylglycerol, free fatty acids, cholesterol esters, sphingomyelins, total cholesterol, HDL-cholesterol, LDL-cholesterol and diastolic blood pressure were more pronounced in men compared to women (std. ß range: 0.073-0.144, all q<0.05). During the weight maintenance period, women demonstrated a lower rebound in HDL-cholesterol, triacylglycerol and diacylglycerol (std. ß range: 0.097-0.164, all q<0.05).

Conclusions:
Men lose more weight and improve more in cardiometabolic risk factors following a LCD but are less able to maintain these improvements after 6 months of weight maintenance compared to women.