Calories, short for kilocalories are a measure of nutritional energy. We eat a combination of fats, proteins and carbohydrates which contain calories and our bodies convert those calories into energy. One gram of fat contains nine calories, while a gram of protein or carbohydrates each contain four calories.
This process of converting calories to energy is called metabolismand includes three phases.
- Phase 1 Basic Metabolic Rateor BMR is your “resting” metabolism, the calories (as
energy) that your body uses to maintain life. Sixty to seventy percent of the calories you consume are used to fuel basic bodily functions like your heart pumping, lungs breathing, hair growing, etc.
- Phase 2 Digestive Metabolismrequires ten to fifteen percent of your caloric intake. Digesting food which includes converting carbohydrates into glycogen or breaking down protein into amino acids is often referred to as the thermic effect of food. The body uses calories to digest calories, about 25 of 100 to digest proteins and about 15 of 100 calories to digest fat and carbohydrates.
- Phase 3 Movement Metabolismincludes the remaining fifteen to thirty percent of your calorie consumption used for walking, running, climbing stairs, movement and exercise.
You can see that of the three, movement metabolism is the phase that you have complete control over. Increasing movement, activity and exercise can directly burn more calories. It is also possible to influence your digestive metabolism into using more calories by increasing your protein intake. Additionally, certain types of exercise including High Intensity Interval Training (HIIT) have been shown to literally increase your metabolism causing increased calorie burning.
The typical adult requires approximately 2100 calories to fuel these three phases of metabolism. It varies greatly by size, weight and activity level and could range from 1600 to 2600 calories. But once this metabolic requirement is met, any calories consumed over that becomes excess and excess calories are converted to and stored as fat throughout the body.
While your body does burn fat and available calories as energy, it is a much more efficient fat storingmachine than a fat burning one. This dates back to our distant hunting and gathering ancestors who experienced either feast or famine. During times when food was plentiful the body would store any excess calories as body fat for use as energy when food was scarce. These fat stores are most prominent as belly fat in males but stored across the hips, waist and thighs of women.
Today we live in a time of constant feast, food and calories are plentiful and we often consume more than our bodies require for metabolic processes and those calories are stored as fat. To eliminate this fat requires a combination of nutrition and exercise. We must eat the right amounts and combinations of foods as we increase our activity level in order to create a caloric deficit to avoid adding additional fat stores and to decrease those fat stores already present.