Why the brain makes weight loss difficult

On August 4, 2026, scientists reinforced that the difficulty in losing weight is not linked to willpower, but to evolutionary brain mechanisms. The human body, shaped by hundreds of thousands of years of scarcity, reacts to diets as if they were threats to survival.

How the brain stores old weight

Recent research indicates that the brain has powerful mechanisms to defend body weight, “remembering” the weight the organism has previously had. When our ancestors lost weight in difficult times, the body could “recover” the usual weight when conditions improved. For modern humans, this record causes the higher weight to be treated as a new set point to be preserved.

Why weight loss triggers hunger responses

When weight is lost, the body reacts as if it were a survival threat: hunger hormones increase, cravings for food intensify, and energy expenditure drops. These adaptations evolved to optimize energy storage and use in environments where food availability varied.

Drugs that mimic intestinal hormones

Drugs such as Wegovy and Mounjaro bring hope by mimicking intestinal hormones that signal the brain to reduce appetite. While some patients achieve positive results, others face side effects that make continuing treatment difficult, and stopping often leads the body to regain the previous weight.

Limitations of treatments and the role of prevention

Even with pharmacological therapies, biology tends to restore the original weight when treatment stops. Obesity, therefore, is not solely an individual problem; it requires societal approaches, such as improving school meals, reducing advertising of ultra-processed foods to children, prioritizing walking and bike lanes in cities, and standardizing portions in restaurants.

Sustainable strategies for those seeking to lose weight

For those who want to lose weight, the emphasis should be on lasting habits, not radical diets. Prioritizing adequate sleep helps regulate appetite, while regular activities – even walking – improve glucose levels and cardiovascular health. Moreover, the early years of life, from gestation up to about seven years, are critical: parents' nutrition, breastfeeding practices, and early habits shape how the brain controls appetite and fat storage throughout life.

With information from ScienceDaily.