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Energy – nothing works without it

Energy is the source of life. Energy is required for even the smallest of movements. Even when sleeping, our bodies still need energy so that our metabolism, heart and breathing function and our body temperature is maintained.

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Our energy suppliers

Our bodies’ main sources of energy are carbohydrates and fats. We can also use protein and alcohol as sources of energy. The energy content of food is measured in kilocalories (kcal) or kilojoules (kJ). One kilocalorie is equivalent to 4.2 kilojoules. Not all types of food contain the same amount of energy. Of all of the food types, fat provides the most energy. Alcohol is also very high in energy. Carbohydrates and protein, on the other hand, have half as many kilocalories:

  • 1 gram of fat provides approx. 9 kcal
  • 1 gram of alcohol provides approx. 7 kcal
  • 1 gram of carbohydrate provides approx. 4 kcal
  • 1 gram of protein provides approx. 4 kcal

illustration of human heart

Energy requirements vary from person to person

The amount of energy we need each day depends on many factors. In addition to our age and gender, body weight and physical activity also play a part. The following overview shows the average amount of energy required by adults of a normal weight who do moderate physical activity.

Guideline values for average energy intake




19 to 25 years old 2400 kcal 3000 kcal
25 to 51 years old 2300 kcal 2900 kcal
51 to 65 years old 2000 kcal 2500 kcal
65 years plus 1800 kcal 2300 kcal

Source: D-A-CH reference values for guideline daily amounts (Umschau / Braus, 2000) dieting and losing weight symbol

The right portions are important

People who consume more energy than their body needs for an extended period will put on weight. It is therefore important to eat in moderation to keep your body weight within a healthy weight range. If you are unsure whether you weigh too much, you can check with our BMI Calculator. Simply enter your current body weight and height. The calculator will do the rest for you. Are you carrying a few excess pounds? Then a combination of more exercise and reduced calorie intake is the most effective way to get back to your ideal weight. Take a look at the Calorie Burn Calculator to find out how many calories you can burn by doing different types of physical activities. man sleeping on grey sheets

When our bodies become energy-savers

A calorie-controlled diet can also be helpful when losing weight. However, not every diet is recommended. Make sure that your meals are varied and balanced and that the diet does not promise significant weight loss over a short period of time. This is unreliable. It is especially important not to let a weight-loss diet become a matter of habit. While you are on this temporary diet, your body will adjust to receiving less energy. It becomes an “energy-saver???. As soon as you start eating normally again, the energy stores will fill up quickly to prepare for the next period of hunger. People’s weight is often higher after they have been on a calorie-controlled diet than beforehand.