What are calories?

Calories are a measurement of energy. One calorie by definition, is the energy or heat required to raise the temperature of 1 gram of water one degree Celsius (or 1.8 degrees Fahrenheit). In other words, a calorie is a unit of energy. We use calories to measure the amount of energy stored in food. Different nutrients have different amounts of energy. One gram of carbohydrates has 4 calories, one gram of protein has 4 calories, one gram of fat has nine calories, and fiber has no calories. We need calories to survive. Too many calories though, and we gain weight. Most women require 1500-2000 calories a day to maintain their weight. Most men require 2000-2500 calories a day to maintain their weight. If you have more muscle, you burn more calories a day. On the other hand, if you have more body fat you burn less. Muscle is more metabolically active than fat. The more activity you do during the day, the higher your daily calories requirements are to maintain your weight. Walking 1 extra mile a day (2000 steps) burns 100 calories. One pound of fat equals 3500 calories. Therefore to lose one pound of  weight, you must eat 3500 calories less than your body requires over a period of time. For example, if your body requires 2000 calories a day to maintain your weight, and you eat only 1900 calories a day you will lose about 1 pound a month and 12 pounds over a year. If you eat 100 calories less and walk an extra mile every day (2000 steps) which equals 100 calories, you will lose 2 pounds over a month or 24 pounds over a year. Losing weight is not rocket science. The goal should be to eat foods that fill you up for less calories – foods that are not calorie dense. Exercise also helps with weight loss. Be careful though, if you exercise more but also increase your caloric intake, your weight may not decrease. This is a common mistake many people make. Many people are frustrated that they are unable to lose weight. This is usually caused by unknowingly eating too many calories or not burning enough off. If you are frustrated, start paying attention to the calories of the foods you eat. Be very careful of serving sizes! Keep a diary for a short period of time if this helps. Losing weight and keeping it off does not have to be complicated. We will be discussing the calorie density of food in future posts. This concept will be critical to helping you lose weight and keeping it off.

Author: drjeffgreenberg

Dr Greenberg is a clinical cardiologist who specializes in preventive cardiology, nutrition, exercise, and longevity. He favors using natural methods to improving one's health.

5 thoughts on “What are calories?”

  1. Actually, the nutrient density of animal products is far greater than that of fruits, vegetables, and whole grains. In addition, plant sources of calories contain xenobiotics(1), chemicals the plant makes that the body can’t utilize. When animals (or humans) consume plants, their bodies routinely process and excrete xenobiotics. When animal foods are consumed by humans, most of the chemicals ingested can be utilized for energy or for body building and tissue repair.

    1. http://en.wikipedia.org/wiki/Xenobiotic

  2. Caloric density may not be as important as micronutrient adequacy. Here’s comment:

    “In my opinion, beyond the absolutely basic requirements, it seems that macronutrients could simply be considered as a vehicle to deliver the optimal amount of micronutrients to our bodies, and our bodies are highly adaptable and capable of making the necessary changes in macronutrient intake to do so. Our body can easily interchange between macronutrients, but it certainly cannot do this for vitamins and minerals, which are essential for life and non-negotiable.” http://civilizedforager.com/2012/08/22/micronutrient-series-are-macronutrients-important/

    1. You bring up an interesting point. Nutrient density and calorie density are closely related. Eating a diet high in nutrient density (high in vitamins, minerals, phytonutrients, antioxidants, and fiber) will lead to a diet that is also low in calorie density. Foods that are highest in nutrient density include vegetables, fruits, and whole grains. On the other hand, processed foods are high in calorie density and low in nutrient density and thus should be avoided. The goal of the diet should be to get as many nutrients as possible for the least amount of calories. Eating a diet that is focused on eating only those foods highest in nutrient density will also lead to weight loss.

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