Weight Cycling Increases Longevity Compared with Sustained Obesity in Mice.

Area of Science:

• Metabolic research
• Longevity studies
• Obesity research

Background:

• Weight loss offers health benefits for individuals with obesity.
• Observational studies link weight cycling (weight loss and regain) to increased mortality.
• The necessity of sustained weight loss for health and longevity benefits is unclear.

Purpose of the Study:

• To investigate if sustained weight loss is required for health and longevity benefits.
• To determine the impact of weight cycling on mortality and lifespan.
• To compare the effects of sustained weight loss versus weight cycling in a controlled study.

Main Methods:

• A randomized controlled feeding study was conducted using obese mice.
• Mice were assigned to groups: sustained obesity, sustained weight loss, or weight cycling (repeated calorie restriction and refeeding).
• Longitudinal monitoring of body weight, composition, food intake, and survival until death was performed.

Main Results:

• Weight loss reduced adipose mass and adipocyte size in both sexes.
• Weight cycling led to regained body fat and adipocyte size during refeeding.
• Sustained weight loss showed a dose-dependent decrease in mortality compared to maintaining obesity.

Conclusions:

• Weight cycling significantly increased lifespan compared to remaining obese.
• Weight cycling demonstrated a similar longevity benefit to sustained modest weight loss.
• The findings suggest that weight cycling may not be detrimental to lifespan and could offer benefits comparable to sustained weight loss.