The amount of energy you’ll get from carbohydrate, protein and fat is measured in calories per gram. Fats have the most energy and proteins have the same amount as carbohydrates, but their value as a source of energy is determined by more than the calories gained from one gram. Other factors, such as your activity level and diet, impact impact which macronutrient is used for energy.
Carbohydrates are the preferred source for energy. Carbohydrates have four calories per gram. Sugars and starches get digested to produce glucose, which is the form of energy preferred by every cell in your body. They also have the advantage of being converted into energy faster than fats and protein. Inside your cells, special structures convert glucose into the chemical that stores and carries energy: ATP. Each molecule of glucose produces 36 to 38 molecules of ATP. If you eat more carbohydrates than you need for energy, the excess glucose is stored in fatty tissue as triglycerides or in the muscles and liver as glycogen.
Even though fiber is a carbohydrate, it passes through your system mostly intact and doesn’t get absorbed into the bloodstream, so it provides very little energy for the body. However, some types of fiber are fermented in your large intestine, producing short-chain fatty acids that are metabolized for energy. This energy may be used throughout your body, but it also helps support the growth of healthy bacteria in the intestine. It’s estimated that each gram of fermentable fiber has 1.5 to 2.5 calories.
When your body runs out of glucose, it turns to fat for energy, which has 9 calories in every gram. This is a little more than double the amount in carbohydrates. Converting fat into energy takes longer than it does to convert glucose into energy, because fat must be first be broken down into its two component parts: fatty acid and glycerol. Each part follows a separate pathway to ultimately become available as energy. One common saturated fat, palmitic acid, makes 130 molecules of ATP for each molecule of fat.
Your body prefers not to use protein for energy because it is specifically needed to build and repair all kinds of tissues. Your muscles, hair, skin, organs, enzymes, antibodies and hormones depend on proteins. In short, proteins have other essential jobs to fill. If you don’t have enough carbohydrates or fats to meet your energy needs, amino acids from dietary protein are converted into energy. Each gram of protein equals four calories.Oppblåsbare bassenger
Original article by Sandi Busch