How many calories should you eat each day?

Studies have shown that even though consumers read nutrition labels and know the calories of food, 9 out of 10 people don't know how many calories they need each day to maintain a healthy weight.

Calories are units of energy contained in food in the form of carbs (starches), fats, and proteins. Calories are used in almost every bodily activity such as: Breathing, getting your heart pumping, talking and walking. If there are excess calories, the body stores the calories as fat. But some calories are stored in the liver and muscles so they can be released quickly into the bloodstream if the body needs energy. Most foods have calories, but with varying amounts of calories. Fat has the highest number of calories. Therefore, understanding the role of calories in your diet can help you balance calories with calories in your body, helping you achieve the desired weight.

An average-weight adult woman needs to eat about 2,000 calories a day to maintain her weight and 1,500 calories a day to lose one pound of weight per week. Meanwhile, the average adult male needs 2,500 calories to stay active and 2,000 to lose one pound of weight per week.

However, the amount of calories needed by each person varies depending on many factors such as: Age, height, current weight, activity level, metabolism and several other factors. Since fat provides more calories, dieters and healthy eaters try to limit the amount of fat in their diet. You can reduce your intake of 500 calories per day. Losing 1-2 pounds per week is considered a healthy and sustainable rate of weight loss. You need to be careful not to cut too many calories and should not follow a low-fat diet because it can be dangerous to health. Certain calories provide special weight loss benefits. For example, calories from protein are helpful in building and maintaining muscle. When you have more muscle, you can stay active and burn more calories. And calories from fiber-rich foods help you feel full and not go hungry throughout the day.

Calculating daily food calories is one of the main techniques people use when trying to lose weight. A calorie is a unit of energy, not a measure of weight or nutrient density. In 1990, the US government passed the Nutrition Labeling and Education Act, standardizing information, including calories, that must be listed on nutrition facts labels. That means before any packaged food in the United States goes on sale, food scientists must measure the nutrients and calories of that product, but in a very complicated way.

The 19th-century American chemist Wilbur Atwater, who identified a way to indirectly estimate the number of calories in food, called the 4-9-4 system. His experiments showed that protein and carbohydrates each have about 4 calories per gram (0.04 ounces) and fat 9 calories per gram, hence the 4-9-4 system. Assuming you have a food that contains 10 grams [0.35 ounces] of protein (10 x 4 = 40) and 5 grams [0.2 ounces] of fat (5 x 9 = 45), the total calorie value is 40 + 45 = 85 calories. However, some nutritionists now believe that Atwater's calculation is outdated and inaccurate. A 2012 study published in the American Journal of Clinical Nutrition found that the energy content of some foods, such as nuts, cannot be accurately calculated using Atwater's calculation. As a result, the Food and Drug Administration allows a margin of error of 20% for nutrients listed on food labels, including calories, which means that these calories may not be entirely accurate.