Healthy and slim thanks to fewer carbohydrates – this is what a low-carb diet is said to achieve. But is this really the case? Let’s find out.
Low-carb refers to a form of nutrition that more or less restricts the intake of carbohydrates. The aim of this method is to reduce body fat and define the body. Sugar and starchy foods are avoided in particular, such as bread, pasta, rice and potatoes. The amount of carbohydrates that are still allowed depends on the low-carb diet.
Carbohydrates are a main nutrient in our diet. They contain around 4 kcal per gram, and occur mainly in the form of sugar (mono- and disaccharides) and starches (polysaccharides). However, pulses, milk, yoghurt, fruit, vegetables, honey and all foods containing sugar contain carbohydrates.
Primarily speaking, carbohydrates deliver energy to our body. The Swiss Society for Nutrition recommends that around 45 to 55% of our daily energy intake should come from carbohydrates. This amount is reduced in a low-carb diet.
Carbohydrates are stored in the liver and in muscle cells. When these stores get full, the body turns the carbohydrates into fat. Generally speaking, people do not want to gain weight, which is why low-carb diets appear to be a sensible type of diet. The idea behind low-carb diets: too many carbohydrates lead to weight gain. Reducing carbohydrate intake means that the body changes its metabolism – just like when fasting. Instead of carbohydrates, it breaks down fat and uses it as an energy source instead.
Various diets rely on the low-carb principle. Well-known diets include the keto diet, Atkins diet and paleo diet.
The keto diet is a low-carb, high-fat diet. Carbohydrate-rich foods such as pasta, bread and rice are a no-go. Fruit is only rarely featured as it contains a lot of fructose. Fat, however, should make up more than half of the daily nutritional intake. Popular foods in the keto diet include fatty fish, meat, eggs and low-carb vegetables such as courgettes and broccoli.
Good to know: our body needs a constant supply of energy. If it lacks sugar from carbohydrates, it will turn to its fat reserves, which it uses to produce a sugar replacement. This is made up of what are called ketone bodies, which is where the diet gets its name from.
There are no restrictions on fat and protein in the Atkins diet. However, one shouldn’t eat too many carbohydrates. Low-carb foods such as salad and vegetables are allowed. Protein sources such as meat, fish, eggs and full-fat milk products are also included in the diet.
The paleo diet is also known as the “stone age” diet. It centres around the nutritional habits of our ancestors. Foods allowed include nuts, berries, dried fruit with no added sugar, meat, fish, vegetables and fresh fruit. Processed ready meals, classic sweets, fast food and grains are forbidden. This means the diet automatically contains fewer carbohydrates and more protein.
It makes sense to adapt energy intake to individual requirements. But even if not much energy is required, carbohydrates shouldn’t be done away with completely. They are essential for the body. Glucose (also known as dextrose) is the only energy source for our brain and red blood cells, for example.
Food rarely contains just one nutrient; it usually contains an entire spectrum of them. For example, starchy foods such as grains and pulses don’t just contain carbohydrates, but also important vitamins and minerals, and ideally a decent amount of fibre, too. In general, the amount and quality of carbohydrates make all the difference. Don’t overdo it with the pasta, but don’t completely remove it from your diet, either. You can, for example, opt for more whole grain varieties. The dietary fibre in whole grains help keep you full for longer and regulate digestion. Make sure that the carbohydrates are rich in dietary fibre and are as unprocessed as possible. The glycaemic index and glycaemic load can help here.
Any diet with an extreme proportion of energy-delivering nutrients – be it fats, carbohydrates or proteins – reduces the choice of food. On the one hand, this means that the body is inadequately supplied with essential nutrients such as vitamins and minerals, and on the other hand, it means it sometimes also absorbs too much energy or fatty acids. Over time, an unbalanced diet has a negative effect on the body.
The nutrient distribution in low-carb diets deviates from the recommendations of the Swiss Society for Nutrition. For health reasons, carbohydrates should never make up less than 10% of your daily calorie intake, even if you are losing weight. However, make sure that your energy intake suits your lifestyle. Energy requirements depend on gender and size, and how much physical activity you do. If you move a lot, you can and should automatically eat more carbohydrates. The body burns the energy contained in the carbohydrates immediately and doesn’t have to store them.
If you want to reduce your carbohydrate intake, you should first keep an eye on hidden sugar. There’s often much more sugar than you might think, especially in sweet drinks, supposedly healthy snacks and processed food.
Sarah Ehmer (Msc in Health Education) joined Helsana in 2019. As a health management specialist, she helps customers engage with prevention and health promotion. Sarah Ehmer gave the editorial team advice and input for this article.