Women may experience better improvement in insulin resistance than men after weight loss.
Weight loss interventions are considered part of the first line of therapy for those who develop disease states associated with insulin resistance, such as pre-diabetes, diabetes, or metabolic syndrome. Gender differences in insulin resistance have been extensively reported, but gender differences in the ability to improve insulin sensitivity are not well-established. However, the question of whether gender can predict the degree of insulin sensitivity improvement after weight loss has not been adequately answered. I have personally observed a difference between the degree of successful loss and maintenance between my wife and I. It sure seems like my wife has more difficulty losing weight and keeping it off. This concern has been echoed in my patient population so it must be that women have more trouble losing weight than men. Multiple studies confirm that a higher fat loss in men with the same intervention. It would make sense that since obesity is tied to increase insulin sensitivity that more fat loss in men would lead to a higher decrease in insulin sensitivity. This research appears to contradict this belief.
Insulin resistance is a strong independent indicator of the risk of developing metabolic syndrome, type 2 diabetes, and obesity. We know that weight loss and exercise both decrease insulin resistance. Central obesity is known to contribute to the development of insulin resistance and metabolic syndrome. This risk is likely due to calorie and energy excess leading to increased insulin. Excess insulin has been shown to increase not only increase abdominal fat deposition. Unfortunately, abdominal fat leads to a reduction of insulin receptors, so it takes more insulin to have the same decrease in blood sugar. Hence it leads to the development of insulin resistance.
A study completed in 2018 attempted to tackle this question. The study looked at a group of 100 non-diabetic subjects who were overweight/obese that were randomly assigned to a walnut-enriched reduced-energy diet or a standard reduced-energy-density diet in a 6-month weight loss intervention. There were no significant differences in weight change, glucose, insulin, or insulin resistance between the two diet groups. The combined groups lost an average of 8.7 kilograms and decreased insulin resistance by an average of 1.4, but the change in insulin resistance was weight change. Despite having a higher weight loss in men and male gender was associated with a lower reduction in insulin resistance when compared to females with the same weight loss and baseline insulin resistance.
The bottom line: The findings from this study suggest that men may have a more difficult time improving insulin sensitivity than women with an equivalent weight loss and baseline insulin resistance. More research is needed, but this could be because men tend to gain more body fat around their waist. This result may mean that insulin-resistant men may require more aggressive intervention.