Sense and nonsense of diets

Diet in obesity? Each diet is only as good as one`s own endurance.

„Each diet is just as good as one’s own endurance”

Diets are a continuous burner. Magazines, especially those for women, are full of it. On time with the fasting period this is also a topic in talk shows.  On occasion of the “Day of healthy nutrition” the IFB AdiposityDiseases takes up the topic diets. The issue as such is always the same: Which one of the countless diets brings the biggest and durable success in the battle against pounds? Yet, the confidence in the power of diets is a mistake. Not the diet determines how much and how long someone looses weight, it’s an individual task. “It depends on the endurance, no matter which diet is chosen”, says Dr. Tatjana Schütz, nutritionist of the IFB. If the person concerned does not ask for too much and too fast a weight loss the dreaded yo-yo effect can be avoided. Simple rules, which one has heard before. Nevertheless, they have to be repeated . Therefore, Dr. Tatjana Schütz explains the golden rules for losing weight – generally and in the special case of obesity.

There is always a discussion about sense and nonsense of diets. Are they appropriate for obese people?

That depends on how the term “diet” is defined. The word “diet” is derived from Greek and means originally lifestyle, respectively conduct of life. A healthy lifestyle, including an adequate  is advisable for obese patients. In the course of time the word’s meaning changed to ‘special nutrition for sick people’. The aim is to positively affect diseases through a targeted selection of food. For obese people the weight reduction has priority. Often people try to achieve this as fast as possible by an “extreme diet” with a unilateral selection of food as with the “pineapple diet” or extremely low energy consumption (e.g. “calorie free diet”). Diets of this type are inadvisable! Furthermore, an appropriate diet is an important component in obesity treatment, besides exercise and compliance.

What basic diets are available and which one promises most likely success?

Reduction diets can be divided into three great groups, due to their nutrients’ composition:

  • the low-carb diets, in which the intake of cereals, rice and potatoes is reduced
  • the low-fat diets, in whichthe fat supply is restricted
  • the energy reduced mixed diet, for example the Mediterranean nutrition, in which fruits, vegetables, fish, high-quality plant oil and meat are preferred associated with a balanced nutrition and a reduction of energy consumption.

Important for all types of diets is a sufficient intake of protein, otherwise the body would reduce the muscle mass. Which diet shows most likely success depends on a negative energy balance. That means energy consumption should be higher than energy intake. This should be achieved for a long time; otherwise weight-reduction won’t work. The composition of the major nutrients – like protein, fat and carbohydrate - does not influence therapy success as much as changing nutrition on the long run. What matters is patient-compliance.

What are the steps of nutrition therapy in obesity? What needs to be considered?

Depending on the degree of obesity, the individual risk profile and the therapeutic target the German Adiposity Society recommends in its guideline “Therapy and Prevention of Obesity” the following four steps:

Step 1: Sole reduction of fat consumption

The consumption of fat is reduced to 60 g per day. The intake of carbohydrates is unrestricted. The daily energy deficit should be at about 500 kcal. This changes lead to a weight reduction of averagely 3.2 to 4.3 kg in a period of 6 months.

Step 2: Moderate energy reduced mixed diet

Additionally to the reduction of fat consumption the intake of carbohydrates and proteins is being reduced. The intended energy deficit is at about 500 to 800 kcal per day. To reach a good satiety, especially the consumption of fiber-rich foods such as vegetables is recommended. This type of nutrition is mostly free from side effects and potent in the long term. It is deemed to be the standard therapy for obesity. In a period of 12 months is a weight-loss of about 5 kg achievable.

Step 3: Meal replacement with formula products

Formula products like special protein drinks or bars can replace one up to two main meals per day. With a daily energy consumption of 1200 to 1600 kcal is a weight loss of averagely 6.5 kg expectable.

Step 4: Formula diet

With a consumption of formula products only the input energy is 800 to 1200 kcal per day with an adequate supply of vitamins, minerals and trace elements. The drop in weight is at about 0.5 to 2 kg per week in a period up to 12 weeks. At the latest after 12 weeks should be a shift to a moderate energy reduced mixed diet such as in step 2 to stabilize weight. A medical and dietetic assistance should be exercised due to the higher risk of sideeffects.

The more the caloric intake is restricted and the longer the diet period takes the more important is the increase of physical activities to support the weight loss.

How can one avoid the yo-yo effect?

The yo-yo effect describes a fast weight gain after the end of a reduction diet. This can lead even to a higher weight than the kilos before the diet. The metabolism adapts fast to the lower energy consumption by reducing the resting metabolic rate. This is negative for losing weight, because fewer calories are burned. Energy that is not consumed migrates to the fat depots.

To prevent the yo-yo effect the energy consumption should not be radically restricted, but be about 500 up to 800 kcal under the needs. The physical activity should be increased to raise energy consumption and counteract muscle reduction. Thus, losing weight is slower – desirable are 0.5 kg per week – but it is more sustainable and the chance of keeping the new weight is higher.

Food should always be tasty and fun. Is this still possible with those diets?

Extreme diets with their one sided food selection respectively very low caloric intake are hard to stand. Fun and pleasure surely comes off badly. When choosing energy reduced mixed diets the balanced nutrient intake can be reached by a broad range of foods. Thus, everybody finds something tasty. However, you have to be moderate in quantity and frequency of eating and drinking. Based on the common nutrition of obese people the nutritionist will give tasty alternatives to “calorie bombs” and inform about low fat ways of cooking. It may be fun to take a diet as starting point for leaving the normal way of nutrition and discovering new flavours.

Are there trends in obesity treatment and how do they look like?

Scentific research indicates that a great number of ingredients may influence energy balance in the body. On the one hand there are roughages in fruits and vegetables. On the other hand  there are ingredients of berries, soya beans, tea and various spices in the focus of the scientists. But there are still no detailed recommendations.

Important for changing to a healthy way of life with losing weight is the direct contact between patient and therapist. Another promising alternative is a more long distance approach, e.g. special online offers with email contact. Even in that case medical advice should be searched, especially in high grade obesity.

Interview of Dr. Tajana Schütz, nutritionist at the IFB AdiposityDiseases, by Carmen Brückner.

Keywords: obesity treatment, nutrition & diet