It is not the amount of calories or how much exercise we do that determines whether we are slim or fat, lose weight or stay plump despite several diets. Studies show that completely different factors are decisive and what we can do about it.

We are all getting older? That is what we assume. But there is one important factor that is pushing down general life expectancy: a quarter of adults are obese. This category includes people with a BMI of at least 30. This increases the risk of numerous diseases from arteriosclerosis to cancer and stroke – and life expectancy is demonstrably shortened by more than ten years.

Obesity is perhaps the most dangerous global epidemic. The number of people affected is increasing every year; according to the Robert Koch Institute, in Germany it currently affects almost 70 percent of men and about every second woman.

These facts are actually inexplicable, because there are countless diets and weight loss programs. But most diets fail, that has long been known. 90 percent of those who want to lose weight actually weigh more than they did before they started the diet, and are victims of the yo-yo effect.

Nutritionists are only now slowly uncovering the reasons for this. One of the most important findings is that a simple equation that was previously considered the first and most important law for weight control does not apply to many overweight people. It was:

Overweight = the person has eaten more calories than burned

“Saying obesity is an energy balance problem is like saying fever is caused by a temperature imbalance,” says Andrew Greenberg, a professor at Tufts University School of Medicine and the Friedman School.

Both views are too simplistic. Fever is a defensive reaction of the body. And a negative calorie balance is not always associated with losing weight. The many overweight people who constantly punish themselves and eat little but still don’t lose weight can tell you this. On the other hand, there are many people who eat more every day than they burn in energy and are still slim.

The second law – if you exercise every day, you’ll get slim – is also being called into question by recent studies. In a study on losing weight through exercise, test subjects gained weight rather than becoming slim as expected. Apart from elite sport, exercise is therefore greatly overrated as a calorie burner. Not even a little bit of recreational sport burns a lot of calories, but in reality our brain is a real energy guzzler. It uses around a quarter of our total energy – even though the brain only makes up two percent of our body weight.

But anyone who thinks they can lose weight by doing brain training and learning languages ​​is also mistaken. The calorie requirement only increases slightly. The brain processes most of its energy, exclusively in the form of glucose, during activities that we are not consciously aware of, such as hormone production and the control of metabolism and organ functions.

So lifestyle must be the deciding factor – our Western lifestyle of constant sitting is often seen as the root cause of the obesity epidemic. A study was able to refute this, too. Scientists compared the daily calorie requirements of typical (sedentary) US Americans with those of an African tribe that lives as gatherers.

The calorie requirements of both groups were the same: around 2,600 kilocalories for men and just under 2,000 for women, although the Africans who still live in their original lifestyle are constantly moving and rarely sit during the day.

However, the gatherers were slimmer than the sedentary Westerners. There are several explanations for this. One obvious one is that those who did not exercise much consumed many more calories every day than their daily requirement (more than 500, which would definitely have a significant impact in the long term).

However, the foods that are eaten are likely to have a much greater influence. And these differ significantly between the two groups. Certain foods are associated with weight gain, others with weight loss, says Andrew Greenberg. His studies have shown that the following foods lead to obesity particularly quickly:

On the other hand, weight loss is supported by:

The scientist goes so far as to say that those who primarily eat these inexpensive foods can eat as much as they want until they are full – and still not gain weight, as is the case with the gatherers, who prefer mainly plant-based food.

The explanation for this lies in the fiber that is abundantly provided by vegetables, fruit and nuts. With indigestible fiber, the body excretes calories that are not used. Plant fibers are proven to make you slim, as another study shows.

In this study, two groups of people wanting to lose weight were allowed to eat the same food with the same daily calorie intake. However, one group ate all of its grain products whole grain, while the other group ate all of its grain products hulled and processed. The whole grain group burned around 100 calories more per day – an amount that can lead to a weight loss of three kilograms in just one year.

Dietary fiber therefore has a positive effect on metabolism. However, metabolism, satiety, hunger and the number of fat cells cannot be fundamentally influenced. Much of this complex interaction is genetic. This is why some people find it easy to lose weight or are slim anyway and stay that way, while others constantly struggle with obesity despite great efforts.

But they can also hope. With the right diet, appetite changes. The desire for healthy food that makes you slim rather than fat increases: for foods rich in fiber such as fruit, vegetables, whole grain products and protein-rich foods such as fish, poultry and yogurt. The appetite for pizza, burgers, chips and sweets disappears.

Sounds untrue? But it’s true, as a six-month study recently showed: Half of the test subjects ate the listed foods rich in fiber and protein, and were also given tips such as eating before lunch because pizza is always served there. The control group, on the other hand, ate normally.

Brain scans were performed on the test subjects at regular intervals, during which they were shown different foods. Little by little, the reward center in the test subjects’ brains reacted more and more strongly to the healthy foods. The appetite for whole grains and fruit increased, and fast food was no longer an attraction. At the end of the study, the test subjects had lost an average of eight kilos, while the control group had gained just under one kilo.

Even if it is difficult for people who are genetically predisposed to losing weight, it can still be achieved with the right foods and a little perseverance. Perhaps it is a small consolation for them that annoying calorie counting has been overrated. This makes it easier to incorporate a healthy diet into everyday life and to lose weight permanently, not quickly.

Many people want to lose weight, but they lack the motivation or time to exercise. A new study shows that even a small reduction in daily calorie intake can help you lose weight and rejuvenate your muscles.

Jörn (56) says he would have liked to have gotten back on track with his ex-wife Heidi. At the same time, he is happy that after 20 years of marriage he is now discovering completely new sides of himself at the side of another woman. How does that fit together? A conversation about the pain of letting go – and the surprise of receiving a gift.