Fatal Spiral: Obesity Begins in the Brain

Brain Chemistry Out of Balance

“Among people with obesity, communication between the body and the brain is disrupted,” says Dr Ruth Hanßen from the University Hospital Cologne during a press conference at the 68th Congress of the German Society for Endocrinology (DGE) on 11 March.

As a result, the brain often cannot accurately interpret signals sent by the body: “For instance, individuals may eat too much even when their body already has enough energy because the brain continues to send hunger signals,” explains the specialist in internal medicine and endocrinology.

Underestimated Role of Insulin

Over time, a sneaky insulin resistance can develop – and this pre-stage is the first step towards type 2 diabetes. In this process, body cells increasingly respond poorly to the hormone insulin.

Its task is to transport glucose from the blood into the cells. When this process becomes less efficient, long-term, not only does blood sugar levels rise, but the brain also develops its own insulin resistance. This means that appetite regulation no longer functions properly.

Problematic Combo: Fat plus Sugar

How powerful this influence is was recently demonstrated by a study at the University of Tübingen involving healthy, normal-weight men.

These men consumed 1500 calories daily in the form of highly processed, unhealthy foods like chocolate bars and crisps for a week. Their brains responded to insulin nearly as insensitively as those of individuals with severe obesity, reports the study leader, Prof Stephanie Kullmann. The researchers observed this effect using magnetic resonance imaging (MRI).

“This effect can still be seen even a week after returning to a balanced diet,” says the scientist. Additionally, the junk food diet significantly increased fat content in the liver.

“You Have to Fight Against the Brain”

“When you have a higher body weight, you have to work against your own brain,” says Dr Ruth Hanßen. The reward centre in the brain doesn’t just regulate food intake – it also influences motivation in completely different areas of behaviour.

For example, whether one can summon the motivation for exercise, studying, or cleaning. Over time, changes in brain chemistry can lead to a lack of drive and reduced performance, the researcher reports. And this, in turn, makes weight loss more difficult.

Can the Changes Be Reversed?

Particularly problematic: the excess fat stores seem to cause long-term changes in the brain. This is another reason why obesity is considered a chronic condition that requires lifelong management.

“The idea that losing weight alone will solve the problem is flawed,” says Hanßen. Whether these effects are reversible is still uncertain. At least animal studies, and some research involving humans, suggest that they probably are not.

What Is the Impact of Industrially Produced Foods?

Since the 1970s, obesity has increased across all age groups. No country in the world has yet managed to reverse this trend. Concurrently, the proportion of highly processed industrial foods has steadily risen. Not just the calorie intake, but also the type of food, could play a role in the global obesity pandemic – evidence for which is mounting.

Lab-produced foods seem to negatively influence not only body weight but also the overall function of the brain’s reward system. The combination of fat and sugar found in many such foods has a particularly strong effect on this system.

“The information about fat and sugar content reaches the brain via different pathways (from the gastrointestinal tract, ed.),” Hanßen explains. The effects then add up in the brain. “I get the feeling that the food industry understood this much earlier than we could scientifically verify,” the scientist adds.

New Medications Help – But Only with Long-Term Use

At least regarding this harmful spiral of weight gain, promising new drugs like GLP-1 analogues such as semaglutide – found in the highly discussed weight-loss injections – appear to offer an effective countermeasure.

These drugs work, among other things, directly on the brain’s reward centre and have a strong appetite-suppressing effect. For the first time, similar weight-loss success on a medication basis is now possible, akin to outcomes previously only seen after gastric bypass surgery.

“These analogues help regulate eating behaviour and steer motivation,” says Hanßen. The problem: when the medication is stopped, patients usually regain the weight. Whether and what long-term effects these drugs have remains unknown.

In the UAE

For the UAE, where rising obesity rates pose significant public health challenges, this research underscores the importance of adopting comprehensive strategies that go beyond diet and exercise. Recognising that obesity involves complex brain mechanisms influenced by lifestyle, processed foods, and hormonal regulation highlights the need for multi-faceted interventions. Policies promoting awareness about healthy eating, reducing the consumption of ultra-processed foods, and investing in medical research and advanced treatment options like medication-based therapies can help break this vicious cycle. Addressing the root causes of obesity at both systemic and individual levels is crucial for fostering healthier communities and reducing the long-term burden on healthcare systems in the UAE.