Underweight: Gaining Weight Healthily in Daily Life

Not everyone wants to lose weight: conversely, many people struggle to gain weight at all. Being underweight can impair performance, weaken the immune system and burden the body in the long term. Anyone who does not gain weight despite normal or even large amounts of food often feels at a loss. This guide shows how healthy weight gain succeeds step by step in everyday life, which foods really help with it and when you should have the cause medically checked.

What lies behind being underweight

One usually speaks of being underweight with a body mass index below 18.5. The BMI is calculated from body weight divided by height squared and is a rough guide, because it does not distinguish between muscle, fat and water. Body build, age and sex also play a role. Some people are naturally slim and perfectly healthy at the same time, others have unintentionally lost weight or, despite all their efforts, do not manage to gain weight.

The causes are varied. At the core there is almost always an energy balance in which the intake lies below the expenditure. This happens almost automatically with a very active lifestyle, physically demanding work, high sustained stress or little appetite. A naturally brisk basal metabolic rate and a genetic predisposition can also play a role: in some families slim body types are simply more common. In young people who are growing, the energy requirement is high anyway.

Behind it, however, there can equally be conditions of the digestive system, for example a gluten intolerance or chronic inflammatory bowel diseases, in which nutrients are absorbed less well. An overactive thyroid, metabolic disorders, infections or medications can also cost weight. Not least, emotional strains, depression and eating disorders play an important role. That is why it is worth taking unintentional or severe weight loss seriously and clarifying the cause, instead of simply eating more.

When you should have it medically checked

You should seek medical advice if you lose weight unintentionally and without a recognisable reason, if the weight loss progresses quickly or if additional complaints occur. These include persistent loss of appetite, digestive problems, diarrhoea, fever, night sweats, exhaustion, a racing heart or striking paleness. Even when the underweight is markedly pronounced or goes hand in hand with a disturbed relationship to eating, for example with a compulsion to control, counting calories to the point of exhaustion or secret vomiting, professional guidance is important. In children, adolescents, pregnant women and older people, being underweight should fundamentally be accompanied medically, since reserves run short more quickly here. This section does not replace a medical diagnosis, but is intended to help you recognise the right moment for an assessment. Precisely with being underweight, a medical search for the cause is the most important first step before you tinker with your diet.

What you can do in everyday life

Healthy weight gain does not mean stuffing yourself with fast food, crisps and chocolate, but rather increasing the energy intake sensibly and in a nutrient-rich way. Plan several meals and snacks over the day, because small, frequent portions are considerably easier with little appetite than three huge plates. Five to six mealtimes are a good rhythm. Keep energy-rich snacks within reach, for example nuts, dried fruit, cheese cubes or wholegrain bread with a nutrient-rich topping, so that you also take in extra energy when out and about.

Rely on strength training in order to build up muscle mass in a targeted way, instead of only putting on fat. Two to three sessions per week with basic exercises such as squats, rows and push-ups set a strong growth stimulus. Muscles make the body more capable, stabilise the joints and shape the figure. Sufficient sleep and the lowest possible sustained stress likewise support the build-up, since chronic stress often dampens the appetite and puts the body into a draining state.

Drink calorie-containing beverages such as milk, cocoa or plant-based drinks rather between meals than directly before them, so that the stomach still has room for eating. Plain water before eating fills the stomach unnecessarily. Anyone who has very little appetite can try to arrange dishes appealingly, to eat in company and to provide variety with herbs and spices. A short walk in the fresh air before eating can stimulate the appetite. As a check, keep a simple food diary to see whether you actually achieve an energy surplus.

Nutrition that supports

With healthy weight gain, nutrient density counts. Instead of empty calories, nutrient-rich, energy-dense foods that provide a lot in a small volume are ideal. These include nuts and nut butter, avocado, high-quality oils such as olive, rapeseed and linseed oil, wholegrain products, oat flakes, legumes, cheese, eggs, oily fish such as salmon or mackerel, as well as dried fruits such as dates and apricots. Bananas, potatoes and rice provide readily usable carbohydrates.

Protein is especially important in building up muscle mass. Good sources are fish, meat, eggs, dairy products such as quark and skyr, legumes, tofu and nuts. With every meal, combine a protein source with complex carbohydrates and healthy fats, so that muscles, energy and satiety come together. Refine dishes with a dash of oil, cream, grated cheese or nut butter to increase the energy density without enlarging the portion. A spoonful of almond butter in the porridge or some olive oil over the vegetables quickly brings additional calories.

Smoothies with oat flakes, banana, nut butter, milk or yoghurt and a little honey are a practical way to take in a lot of energy in drinkable form, especially when solid food is difficult. What remains important is a balanced, varied diet, so that you gain not only weight but also all the necessary vitamins, minerals and fibre. Anyone who eats purely plant-based should pay particular attention to protein combinations and vitamin B12.

Nutrients & plants with a connection

In the build-up of muscle mass and an active metabolism, several nutrients are relevant. Proteins contribute to an increase in muscle mass and to the maintenance of muscle mass. The amino acids they contain are the building blocks of the proteins. The B vitamins contribute to a normal energy metabolism, and vitamin B6 as well as B12 contribute to a normal protein and glycogen metabolism. Vitamin B12 additionally contributes to the reduction of tiredness and fatigue.

Zinc contributes to a normal metabolism of macronutrients and to a normal protein synthesis. Magnesium contributes to a normal muscle function and to a normal energy metabolism. Iron contributes to a normal oxygen transport in the body and to the reduction of tiredness, which can be relevant with exhaustion. From the plant world, bitter substances, for example from gentian, wormwood or centaury, are traditionally used to stimulate the appetite. Ginger is traditionally used to support digestion. These statements describe EU health claims and traditional uses of individual substances, not the treatment of being underweight.

Common thinking errors when gaining weight

Many who want to gain weight underestimate how little they actually eat. The impression of eating constantly is often deceptive, because the feeling of satiety sets in early in slim people. A second error is reaching for highly processed, very sugary foods in the hope of quick kilos: this burdens the metabolism and provides hardly any building blocks for muscles. Doing without exercise is also a mistake, because without a training stimulus the additional energy ends up predominantly as fat on the belly instead of as muscle. Finally, many expect results too quickly and give up after two weeks. The body needs time and a lasting, moderate energy surplus in order to build up steadily.

Honestly put into perspective

Gaining weight healthily is rarely a question of individual preparations, but of patience and a clever strategy: more energy from nutrient-dense foods, regular meals and strength training for real muscle mass. This takes time, because one to two kilograms per month are more realistic and healthier than quick jumps. Food supplements such as protein or amino acid products can complement a protein-rich diet, but do not replace a balanced diet. No product remedies being underweight. Because being underweight can also indicate a condition, a medical assessment remains the most important step before you tinker with your diet.

Suitable products from Scheunengut

Anyone who would like to accompany a protein-conscious diet will find with us the Amino Acid Complex. It contains all essential amino acids as building blocks of the proteins as well as complementary co-factors. This is a food supplement and not a statement about the treatment of being underweight, but rather a possibility to include amino acids as a supplement to a protein-rich, balanced diet in your routine.

Frequently asked questions (FAQ)

From when is someone considered underweight?

One usually speaks of being underweight from a body mass index below 18.5. The BMI is, however, only a rough guide value that does not take muscle mass and body build into account.

How can I gain weight healthily?

Increase the energy intake via nutrient-dense foods such as nuts, oils, wholegrain and protein sources, eat small meals regularly and build up muscle mass with strength training.

How quickly should I gain weight?

Realistic and healthy are usually one to two kilograms per month. Rapid weight gain through highly processed, sugary foods is unfavourable for health.

Do snacks help with gaining weight?

Yes, small energy-rich snacks such as nuts, dried fruit or smoothies between the main meals increase the daily energy intake without overwhelming the stomach with huge portions.

Is strength training sensible for gaining weight?

Very sensible. Strength training ensures that the additional energy flows into muscle mass instead of only being put on as fat, and makes the body more capable.

Which beverages help with gaining weight?

Calorie-containing beverages such as milk, cocoa, plant-based drinks or homemade smoothies provide additional energy. Drink them ideally between meals, so that the stomach still has room for eating.

When should I see a doctor about being underweight?

With unintentional or rapid weight loss, additional complaints or marked underweight, you should seek medical advice in order to have possible causes clarified.