Anyone wanting to change their figure looks for a diet that suits them. Unfortunately, however, most diets are based on calorie restriction, meaning we eat less. This is unpleasant on the one hand, as it leads to feelings of hunger and energy loss, and on the other hand, it does our metabolism no favours. If we simply cut calories, we are more likely to lose muscle than fat. And particularly with very strict, so-called crash diets, the yo-yo effect inevitably follows as soon as we end the diet and return to our normal eating habits.
Figure problems can be caused by hormonal changes, which in turn can be exacerbated by diets and the resulting nutrient deficiencies, trapping us in a vicious circle. So there is no simple miracle recipe to help the metabolism – only a balanced diet tailored to individual needs.
What happens in my body during a diet in relation to metabolism?
Calorie Restriction
When we go on a diet based on reducing our calorie intake, the body has to draw on its reserves to produce energy. That's the theory, at least. And it does work. However, the sugar stores in the muscles are emptied first. The initial weight loss comes from the fact that less water is now being retained. Producing energy from fat reserves is a strenuous process for the body. When it has to rely on this, we lose energy for other activities. We become more sluggish, and so does our metabolism. When we have less energy and less desire to move, our circulation doesn't get going properly and we end up holding ourselves back. If we then also consume too little protein, the body has to draw on the protein building blocks from its own reserves – the muscles – for repair processes. This leads to a loss of muscle mass, which is particularly unfortunate, as our muscles are energy consumers and actually help us burn calories.
When crash diets drastically reduce calories, every person's individual basal metabolic rate – the energy needed per day simply to survive, regardless of activity – comes under threat. If we give the body less food than it needs for this, it has to make up the deficit from its reserves – and it does. If this undersupply persists over a longer period, the body switches to an emergency programme. This is how nature intended it, to survive difficult times such as famines. The body's basal metabolic rate is downregulated. This means it adjusts to maintaining the most essential systems with a minimum of energy expenditure. For us, this means our weight loss initially stagnates. If we then return to eating at a normal calorie level after the diet, we inevitably gain weight, as our body, now programmed for lean times, no longer needs as much energy for its basic maintenance. With this method, we would have to eat less and less to maintain our weight. But in the long run, this makes us ill, because so many essential nutrients are no longer available in sufficient quantities to optimally maintain all bodily functions.
Muscle Loss
Muscles are our allies when it comes to our figure. They not only give us shape and posture, they are also energy consumers. Our muscle mass has a direct effect on our basal metabolic rate. This means they burn calories – and not only when we train them, but even when we are not using them at all. The more muscle we have, the better our metabolism works and the more calories we can consume each day.
If a diet then leads to an undersupply of protein, the body has to draw on its stores in the muscles to meet its daily requirement of this nutrient. It effectively starts consuming itself; we gradually lose our energy consumers and slow down our metabolism.
Yo-Yo Effect
What is the yo-yo effect and how can I avoid it?
The yo-yo effect describes what happens when we have been on a diet with severe calorie restriction and our metabolism has slowed down as a result. When we start eating normally again, our weight rises once more, just like a yo-yo that has been lowered on its string and only appears to roll back up on its own. The weight gain happens almost as quickly as the loss, and if we repeat the process over the years, the development can escalate to the point where the weight gain even leads to ever higher weights than the original starting point.
Hormonal Changes
Hormones control all our bodily functions and therefore play a decisive role in metabolism as well. As is well known, the thyroid hormones are particularly important here. Almost everyone knows that an underactive thyroid can lead to weight gain.
But stress hormones also have an impact on our metabolism. First and foremost, cortisol. We primarily need this hormone to become active. Especially in the morning, we wouldn't even get out of bed without cortisol. However, if cortisol levels remain high throughout the day, or are repeatedly driven up by stress, this puts the brakes on our metabolism. In evolutionary terms, this hormone served to prepare us for flight or fight. To this end, all less important or efficient bodily functions were deactivated – including fat metabolism, as it represents too slow and laborious a form of energy provision. So if we are under constant stress, fat burning is out of the question.
For figure problems of unclear origin, it is therefore always advisable to have hormone levels checked via a blood test. Often, the metabolism can be helped by adjusting the micronutrient supply.
"There is no simple miracle recipe to help the metabolism – only a balanced diet tailored to individual needs."
Frequently Asked Questions
Diet undoubtedly has the greatest influence on metabolism. When the body is supplied with everything it needs, it can function well. If we supply too much energy, it is stored in the form of fat deposits. If we supply too little, metabolism slows down and goes into a sort of energy-saving mode.
Metabolism can be accelerated through a balanced supply of all important nutrients and through physical activity. But sufficient good-quality sleep is also necessary for this.
With increasing age, metabolism slows down. Factors that contribute to this include a less than optimal supply of nutrients and declining physical activity. Hormonal imbalances may also play a part. Damage to the metabolism from previous diets can also be a factor. The good news is that all these factors can be reversed with a balanced diet and sufficient exercise.
How can I maintain my metabolism after losing weight?
Anyone interested in sustainable weight loss should focus from the outset on achieving this through an activated metabolism, rather than by withholding energy in the form of calories from the body. Those who boost their metabolism through a balanced diet and physical activity will be able to reduce their weight. However, all these changes should be implemented not as a short-term diet, but integrated into one's life on a long-term basis. Only in this way can lasting results be achieved and the metabolism remain active.
Many diets rely on eating nothing or very little in the evening. This poses several problems. Firstly, it makes sense to supply the body with protein in the evening, as it can use the building blocks from amino acids to carry out its repair work during sleep. But carbohydrates are also needed at night to produce hormones, above all serotonin, which is necessary for good sleep and genuine recovery. If we eat nothing or too little in the evening, this can lead to low blood sugar during the night. This in turn causes restlessness and sleep disturbances, and without good sleep, our metabolism cannot function properly. It is certainly not advisable to go straight to bed on a full stomach, as the digestive activity then prevents us from switching off. But a balanced, not overly large meal two hours before bedtime is definitely recommended.
As a general rule, metabolism, like all bodily functions, works best when we are well supplied with all essential nutrients. B vitamins regulate the energy balance; the amino acid L-carnitine helps to transport fat molecules into the cells for energy production; chromium can contribute to regulating insulin levels. The amino acid L-tyrosine, as well as iodine and selenium, are vitally important for thyroid function. So there are various levels at which the right micronutrient supply can do a great deal for a functioning metabolism.
As a rule, metabolism becomes slower with increasing age. However, we can counteract this with targeted nutrient supply and regular physical activity.
Fundamentally, calorie intake should be matched to requirements. During periods of low activity, it is not advisable to supply too much energy, which would then be stored as fat reserves. During phases of increased energy demand due to heightened activity, calorie intake should be appropriately increased so the body can deliver the corresponding performance.
On the other hand, metabolism also follows calorie intake. If we have slowed it down through calorie-restrictive diets, we can get it going again by consistently providing more energy in the form of food. In the first instance, this does lead to weight gain, but in the long term, metabolism then readjusts to a higher energy level, which means we can eat more again and also regain greater performance capacity.
It is very important to eat sufficiently and, above all, to ensure that we supply ourselves with all the important nutrients. The body should not be forced into energy-saving mode. In addition, a healthy amount of exercise is needed. The guiding principle here is: you have to invest energy to gain more energy. However, sufficient good-quality sleep should not be neglected either, because without recovery, we cannot function in the long run.
Thyroid hormones play a decisive role in regulating metabolism. With an underactive thyroid, metabolism is slowed down and weight gain occurs. With an overactive thyroid, it can be difficult to maintain body weight, and other unpleasant symptoms such as restlessness also occur. For figure problems that cannot be clearly explained by eating habits, it is always advisable to have thyroid hormone levels determined through a blood analysis.
Sport and exercise boost the metabolism. During cardiovascular training, the body is activated and, at the appropriate heart rate zone, it can optimally burn fat. The rule of thumb here is that you should run without getting out of breath – that is, ensure there is always enough oxygen available. In principle, this optimal heart rate zone for fat burning can be calculated using the formula 220 minus age multiplied by 0.7. However, as there are individual variations, it is advisable to have the value determined through a spiroergometry test if you want to know precisely.
But strength training also has a positive effect on metabolism, as muscles are energy consumers. The more muscle we have, the more calories we can burn. And this applies even at rest, by the way. So it is well worth investing in building muscle.
The best diet is no diet at all. Only through a long-term change in our eating habits that can be permanently reconciled with our life and our preferences can we sustainably change our figure and maintain a healthy metabolism.
Those who repeatedly go on diets and veer from one extreme to the next destroy the natural regulatory mechanisms of their metabolism. All diets that are based on restrictions in terms of calorie intake or, for example, in terms of carbohydrates or fat, lead to a one-sided diet and deficiency symptoms in a wide variety of vital nutrients. This has a negative effect on metabolic function, as our body as a system can only work when all the necessary substances are present and interacting with one another. And ultimately, the production of hormones also suffers from a lack of building blocks – for nutrients are nothing other than building blocks for the body – hormones that control not only our metabolism but all bodily functions and our entire drive.
There are certainly genetic factors that influence metabolic functions. However, it is far more the habits and the eating behaviour modelled by our parents that we learn from them which determine our physical health and also our figure.
