A small 2023 study of adults with obesity in China found that an intermittent energy restriction program was associated with weight loss and changes in gut bacteria alongside altered activity in brain regions linked to appetite, cravings and self-control.
Researchers in China followed 25 adults with obesity through a two-part intermittent energy restriction (IER) program designed to reduce energy intake on alternating days.
The intervention began with a 32-day “high-controlled fasting phase,” during which participants received dietitian-designed meals and had their calorie intake reduced stepwise to about one-quarter of their basic energy needs. It was followed by a 30-day “low-controlled fasting phase,” in which participants were given a recommended food list rather than prepared meals; full adherence to the plan would amount to about 500 calories per day for women and 600 calories per day for men.
By the end of the intervention, participants had lost an average of 7.6 kilograms—about 7.8% of their starting body weight. The researchers also reported improvements in several metabolic measures, including reductions in blood pressure, fasting plasma glucose and cholesterol measures.
Brain scans in the study showed changes in activity in regions the researchers linked to appetite, cravings and self-control, while stool testing indicated shifts in gut bacteria. The findings point to a possible connection between changes in the gut microbiome and brain activity during weight loss, though the study was small and cannot establish cause and effect.
