Very few people are really aware of how many or, depending on the situation, how few kilocalories we burn every day and how much energy we need in the form of food. Although sport is an essential factor for effective weight control, it is often overestimated in terms of calorie consumption.
Balance burning and eating
How to calculate your energy consumption
Our body is an engine that needs to be regularly fed with energy in order to function. Carbohydrates, fats and proteins – the body converts these food building blocks into glucose, fatty acids and amino acids to fuel the organs. The amount of calories needed to maintain basic vital functions is called the basal metabolic rate. People with a high basal metabolic rate are among the lucky ones who can eat without worrying about gaining weight. Because the higher a person’s basal metabolic rate, the better they utilize the energy from the food. People with a high basal metabolic rate therefore have fewer problems with obesity than people with a low basal metabolic rate.
Modest basal metabolic rate
If we lounged on the sofa all day, the basal metabolic rate of an adult would be between 1,300 and 1,800 kilocalories, depending on how heavy and old he or she is. This is roughly equivalent to the amount of energy contained in two sausages and French fries. Most of the calories are consumed solely by the liver, kidneys, heart and skeletal muscles.
At rest, the liver and muscles together require more than 50 percent of the energy supplied. But the brain also devours 18 percent of the basal metabolic rate every day, which is roughly equivalent to the energy of two bananas.
The average basal metabolic rate can be roughly determined using the “Harris Benedict formula”, which reads:
- Men: Basal Metabolic Rate = 66.5 + (13.7x weight in kg) + (5x height in cm) – (6.8x age).
- Women: Basal Metabolic Rate = 655.1 + (9.6x weight in kg) + (1.8x height in cm) – (4.7x age).
According to this formula, a 50-year-old, 1.80 meter tall, 80 kilogram man has a basal metabolic rate of 1722 kilocalories per day. A 50-year-old, 1.60 meter and 60 kilogram woman has 1294 kilocalories. If they do not increase how much they burn, they cannot eat much before being at a caloric surplus.
If you want to know exactly, you can have your individual basal metabolic rate professionally measured. The results for men and women usually differ considerably. If two people are the same age, weigh the same and are of the same sex, this does not mean that their basal metabolic rate is identical. In addition to height, gender, weight and age, it also depends on how much muscle and fat the body contains. Temperature and air pressure, stress hormones and thyroid gland as well as genetic factors also influence the basal metabolic rate.
1. Weight and height
Large and heavy people have a higher basal metabolic rate in absolute terms than small, light people. This makes sense because they have more mass to support and their organs are larger. So more energy is needed to regulate the body’s functions. Relatively speaking, shorter people have a higher basal metabolic rate. This is because they have a proportionally larger body surface area and therefore require more energy to generate heat.
Men have a higher basal metabolic rate than women because of their larger muscle mass.
Young people have a slightly higher basal metabolic rate than older people. Because muscle mass decreases with age and metabolism slows, basal metabolic rate decreases by about three percent per decade of life after age 30. So a 50-year-old uses less energy at rest than a 20-year-old, even if both weigh the same and are the same size. In order to prevent ourselves from gaining weight as we age, we must therefore either change our eating habits in the long term, do more sport – or build up new muscles.
4. Body composition
Muscle is a sure guarantee for a high basal metabolic rate, because muscle tissue has a more powerful metabolism than fat: each kilogram of muscle mass burns about 60kcal more energy per day than a kilogram of body fat. Extrapolated to a month, this corresponds to 1800kcal, to a year even 21600kcal! Strength training can therefore increase the basal metabolic rate. The body converts fat into muscle and builds up additional muscle mass. These burn more calories – even at rest.
Fortunately, the basal metabolic rate is not all that concerns our energy balance. The body also has to fire the muscles with glucose for every step we take – and that consumes additional calories. Even the biggest slackers don’t lie quietly on the couch all day. We all get up at some point, wash up, get dressed and go to work. This results in an individual “activity factor” for each person, also known as PAL value (Physical Activity Level). When standing, we consume about twice as many calories as when sitting, because the trunk and leg muscles have to keep the body in balance. In general, the more and the more frequently muscles are used in daily activities, the higher the calorie consumption.
Doubling and more
People with a PAL value of 2 or higher double their basal metabolic rate daily. You can increase it even more with exercise, because during physical exertion, energy consumption increases again considerably. The multiplication factor in comparison to the basal metabolic rate can vary between 4 (very moderate exercise) and 12 (very strenuous activity) per hour and even increase to a factor of 20 in elite sports.
Exactly how much energy is converted during athletic exertion depends on numerous factors; these include exertion intensity and volume; body weight, training condition and economy of movement, climate conditions and, last but not least, the terrain profile. It is therefore almost impossible to assign a specific calorie consumption to a sport across the board.
In general, however, it can be said that sports such as running, cycling, cross-country skiing, swimming and rowing, in which large muscle groups are in continuous use, burn a higher amount of energy than, for example, table tennis, technical disciplines in athletics or volleyball in the same amount of time.
Sport and nutrition combined
What’s crucial for successful weight control is that every step you take burns calories. And if you burn more calories than you eat, you can reduce your weight. The best way to lose weight or to keep it off, is a mix of plenty of exercise and healthy eating. Knowing how many kilocalories you burn and how many you eat. As long as your input is not greater than your output, you have nothing to worry about.
If you’re happy with your weight, it’s okay to indulge on days when you exercise – like a piece of cake, two scoops of ice cream, or a small bowl of chips. After all, you’ve burned more calories by exercising.
But don’t make the mistake of overestimating the calories you burned while exercising. Unfortunately, it is often smaller overall than you think. Or downplay the input. Snacking on a bar of chocolate as a reward for a half-hour long run would therefore be too much of a good thing. After all, half an hour of running consumes around 300 kilocalories. But a bar of chocolate has 550 kilocalories, almost double that.
Text from FITforLIFE– This blog post was provided to us by the Swiss magazine FIT for LIFE. If you want to read regularly informative knowledge articles in the field of running and endurance sports, click here.