Every part of our body, including the brain, muscles, heart and other major organs, needs energy in order to function properly. Energy comes exclusively from the nutrients absorbed from the food we eat. When we eat, food is digested and breaks down into glucose, which is a type of sugar found in the blood. Insulin then helps deliver glucose to cells, where it is used for energy.
Macronutrients
There are three main macronutrients necessary for providing energy to the body -- carbohydrates, protein and fat. Carbohydrates are converted into energy more quickly than proteins and fat. Proteins -- which come from animal-based foods as well as plant-based sources such as beans, lentils and soy -- are an important source of calories and energy. When your carb stores are low, your body will turn to protein for energy. Fat is the most concentrated energy source the body has. It's also responsible for proper growth and development and absorbing certain vitamins.
Requirements
Getting the proper amount of these macronutrients is crucial in maintaining energy levels. The McKinley Health Center, part of the University of Illinois at Urbana-Champaign, suggests getting from 10 to 35 percent of your total daily calories from protein. Protein is found in poultry, fish, cheese, legumes and milk. Healthy fats should make up 20 to 25 percent of your daily calorie intake. Fats are found in meat, poultry, dairy, nuts and fish. Carbohydrates should make up the largest portion of your daily calorie intake at 45 to 65 percent of your total calories. Carbohydrates are found in fruits, dairy, yogurt, beans, nuts and seeds.
Recommendations
Although your body needs food for energy, eating too much can cause weight problems, heart disease, diabetes and other chronic health conditions. Carbohydrates and protein contain four calories per gram, and fat provides nine calories per gram. Based on a 2,000-calorie diet, about 200 to 700 calories, or 50 to 175 g, a day should come from protein. About 900 to 1,300 calories, or 225 to 325 g, a day should come from carbs. About 400 to 700 calories, or 44 to 78 g, a day should come from fats.
Skipping Meals
The most common reasons people give for skipping meals is lack of time or in effort to lose weight or reduce calorie intake. Any time you skip a meal, however, your body can go into fasting mode, according to Lara Engler from the National Strength and Conditioning Association. Going too long without food causes your body to deplete glycogen stores in the liver and muscles. If glucose levels get low enough, your body can start breaking down muscle and liver for energy. Headaches, fatigue, constipation and low blood sugar are all signs that your body needs energy. Going just hours without eating, according to Columbia University's Go Ask Alice, can deprive the brain of glucose and lead to feeling irritable and dizzy. Not eating regularly puts you at risk for hypoglycemia and nutritional deficiencies. It can lead to stunted growth in young people.
References
- McKinley Health Center: Macronutrients
- MayoClinic.com; Healthy Diet: End the Guesswork With these Nutrition Guidelines; February 2011
- Go Ask Alice; Will Skipping Breakfast and Lunch Lead to Weight Loss?; October 2007
- "Performance Training Journal"; Nutrition; The Importance of All Meals; Lara Engler
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