What decides whether fat is burned or stored?

Generally, obesity is caused by a long-term intake of energy that exceeds the amount required to expend it, i.e. physical activity. However, whether fat and other nutrients consumed when we eat are burned or stored away depends on how much blood sugar levels (and thus insulin levels) increase after eating – i.e. on how many carbohydrates the food contains and in what quality.

Many factors play a role in the development of obesity and, just like many other diseases, it is strongly determined genetically. However, these “thrifty” genes only apply in certain unfavorable circumstances of modern times including stress, lack of exercise, sleep disorders and poor diet, the order of which is unimportant. These circumstances also apply to everyone to a different degree.

How does sugar turn into extra kilograms?

Insulin plays an important role in the creation of fat deposits, as it stores excess energy into fat deposits and simultaneously prevents them from being used.

Insulin levels are increased primarily by sugar and starch in food. Insulin controls blood sugar levels by shifting it to cells, where it then helps process this sugar. The cells then burn glucose, and what goes unused is stored in the liver and muscles or (to a small degree) in fat tissue. Excess fat consumed along with glucose in food is of little use as a source of energy after eating (as the cells are forced to prefer glucose), and therefore it is stored – by insulin – in fat stores.

For the last 40 years, nutritional recommendations have focused primarily on reducing the consumption of fats, and the food industry has swiftly responded by offering many low-fat and fat-free products. However, the majority of these products are full of sugar and starch – which quickly breaks into sugar and therefore has similarly negative effects.

Low-fat products usually have a weak effect on satiety and cause hunger very quickly. This is intensified by greater variability of insulin levels due to the higher amount of sugar and starches. Paradoxically, they may ultimately lead to a higher caloric intake.

If a low-fat diet consists of nutritionally rich sources of carbohydrates (vegetables, fruit, wholegrain cereals and legumes) and contains a minimum of added sugars and refined carbohydrates, it can lead to successful weight loss. However, a prerequisite for success is the monitoring of the overall caloric intake.

A simpler solution to obesity than eating everything and constantly counting calories is a low-carb diet based on quality foods.


Why does a low-carb diet reduce meal frequency?

A lower carb content in a diet leads to a smaller increase in blood sugar and insulin after meals and thus to a lesser tendency to store nutrients in fat stores. The smaller variability of insulin and blood sugar levels also leads to less frequent feelings of hunger. Food with enough fats and proteins accompanied by vegetables keeps a person full for longer and allows for greater intervals between meals.

Sufficient gaps between meals, combined with low insulin levels, are important, as this is the only way to mobilise fat from fat stores for energy. In a stricter version of the low-carb diet, ketone bodies play a beneficial role – they suppress appetite. This makes the reduction of excess adiposity even easier.

A low-carb diet is seen as a little restrictive (in terms of sources of carbohydrates), but its great advantage is that it is usually unnecessary to count calories and it does not trigger hunger pangs. For some, it can also be more interesting taste-wise than a diet based on healthy carbohydrates – instead of buckwheat and lentils, they might prefer meat and vegetables. Another important rule is to eat when you are hungry, eat until you are full (but do not overeat), and only eat again when you are hungry (without snacking between meals). People normally only need to eat two or three times a day.

If you are overweight and also have diabetes, a low-carb diet also offers another advantage – it will help you lower your blood sugar levels.