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The energy-providing substances and calorie burning in theory and practice

The energy-providing substances and calorie burning in theory and practiceThe body makes energy by breaking down the essential macronutrients, carbohydrate, protein, and fat. Even alcohol provides energy.

  • Carbohydrate: Grain, bread, potatoes, rice, corn, fruit, and sugar
  • Protein: Meat, fish, shellfish, eggs, dairy products, legumes (beans, peas and soy) and nuts
  • Fats: Fat from meat, fish and eggs, plant oils, avocado , nuts, kernels, sees, and dairy products
  • Alcohol: Does not provide nutrients and is an unnecessary source of energy

Different calculations show how much energy one can extract from 1 gram of carbohydrate, protein, or fat.
The energy amounts are specified in kJ (kilojoule) or the somewhat older term kcal (kilocalories)

Energy substance Energy per gram Energy per gram
Carbohydrate 17 kJ 4 kcal
Protein 17 kJ 4 kcal
Fat 38 kJ 9 kcal
Alcohol 30 kJ 7 kcal
4.2 kJ equals 1 kcal

Energy in selected foods in kJ/kcal per 100 grams or 100 ml
Rye bread 800/190 Eggs 630/150 Butter 3000/714 Potatoes/ raw 340/80
Wheat bread 1020/240 Lean meat 557/133 Olive oil 2289/624 Carrots 150/35
Pasta /unboiled 1520/360 Cod 330/80 Peanuts 2.374/566 Frozen broccoli 230/55
Rice/unboiled 1480/350 Fat sausage 2200/520 Cookies 2.124/506 Mixed candy 1.500/357
Mixed fruit juice 190/45 Vegetable juice 70/17 Cafe latte 376/89 Red wine 304/72

Know your different calorie terms – they are often referred to incorrectly and may confuse

  • 1 calorie (cal) is the old term for the amount of energy required to heat 1 gram of water 1 degree (= gram calorie)
  • 1 kilocalorie (kcal) is the amount of energy required to heat 1 kg/liter of water 1 degree (1 kcal = 1,000 calories).
  • Kilojoule (kJ) is a more recent term, where 1kJ equals 0.24 kcal.

Did you know that 100 grams of peanuts contains more calories than a meal with chicken, vegetables, and 1 teaspoon of oil?

Energy consumption and requirement

Your need for energy/calories depends on various factors such as gender, age, weight, ratio between fat and muscle mass, fitness level, metabolic rate, dietary habits, and amount of physical activity.
Women generally need fewer calories than men do (and their calorie requirement goes down after they reach their 50s and 60s).

The daily energy consumption is divided into three categories:

  • The basic metabolism ensures proper functioning of essential functions such as respiration, heart contractions, growth etc. In physically inactive and sedentary people, the basic metabolism consumes 60-70% of their energy.
  • Digestion is the part of the metabolism that handles absorption, utilization, and storage of food. The digestion uses around 10% of the energy.
  • Physical activity is the part of the metabolism that manages all physical activities, ranging from a simple thing like using a cell phone to completing a marathon race. Depending on a person’s level of activity, physical activity may consume anywhere from 15 (physically inactive) to 300% (active athletes) percent of the energy.

Calculating your energy consumption

There are many different ways to calculate your energy consumption, some more complicated than others. The schedule below (which is only a guideline) shows different women’s daily energy requirement. The women are aged 20-50 years, they get eight hours of sleep per night, and their activities differ widely.

Woman (20-50 years old) 50 kg
Energy requirement kJ/kcal
60 kg
Energy requirement kJ/kcal
70 kg
Energy requirement kJ/kcal
80 kg
Energy requirement kJ/kcal

Physically inactive. Has a sedentary job and spends much of her free time sitting down. Only on her feet for about one hour daily.

 Ca. 6,720 /1,600  7,600 /1,800  8,400/ 2,000  9,660 /2,300

Physically quite active. Sedentary job. In her free time, she spends one hour daily on her feet and half an hour daily doing moderate exercise like walking or bicycling.

 Ca. 7,500/1,800  8.600/2,000  9.700/2,300  10.700/2,500

Physically active for shorter periods. Sedentary work. Spends one hour of her free time on her feet, and one hour is spent on intensive training or fast running.

 Ca. 9,300/2,200  10,800/2,600  12,300/2,900  13,500/3,200

Moderately active for longer periods. On her feet for two hours daily Spends three hours on activities such as walking, cleaning, gardening, bicycling, and golfing.

 Ca. 9,800/2,300 11,300/2,700 12,900/3,000 14,200/3,400

Important: Notice how much energy is used, as soon as a person gets up, moves about, and engages in lighter activities.

Energy distribution and effective calorie burning

According to the Nordic Nutrient Recommendations, the energy distribution in the diet should be as follows:

Energy source Normal population
Energy percentage
Trained athletes
Energy percentage
Carbohydrate 55-60 60-35
Fat Max. 30 25-30
Protein 10-15 10-15

If you want to lose weight, it may be a good idea to shift to a higher protein percentage, as protein helps maintain/build muscle mass and it regulates blood sugar and metabolism.
The protein share should not exceed 30%, and it must be divided evenly on the main meals of the day.

Important! Remember that the amount of calories in food does not say anything about absorption, calorie burning and satiety.

For instance, if your rye bread contains whole flaxseeds, the bread contains more calories than rye bread without flaxseeds. This is because flaxseeds contain a lot of oil, and there is roughly twice as much energy in one gram of oil as in one gram of carbohydrate.

If you want to lose weight, you are still better off with rye bread that contains flaxseed than with bread that does not. Firstly, your digestive system does not take up flaxseeds or the oil inside them if the seeds are whole. Secondly, there are fibers in the seeds that help the digestive system with getting rid of other fats and with slowing down the food uptake, which stabilizes your blood sugar, your combustion and digestion.

Get in the habit of focusing more on the quality of your diet than on counting calories

It is normally recommended to strive after a negative energy balance for a longer period, where you reduce your daily energy intake by around 2,000 to 4,000 calories (approx. 500 – 1,000 kcal). However, because the body cannot keep track of its calories, you are better off focusing on the quality and composition of your diet in order to get stable blood sugar and an effective combustion. In other words, it is better for satiety if you eat a chicken breast with mixed salad and a good vinaigrette dressing than if you eat pizza or a slice of bread with jam – even if all the choices contain the same number of calories.

It is best if you can lose around 0.5 to 1 kilo per week. That way, you lose fat and not muscle, and you avoid getting saggy skin.