You are counting them and cutting them, and you would be hard-pressed to find something at your supermarket that does not list its calories per serving somewhere on the package. But what is a calorie is?
A calorie is a unit of energy. We tend to associate calories with food, but they apply to anything containing energy. A gallon (4 liters) of gasoline contains about 31,000,000 calories.
A calorie is the amount of energy, or heat, it takes to raise the temperature of 1 kilogram (2.2 pounds) of water 1 degree Celsius (1.8 degrees Fahrenheit). One calorie is equal to 4.184 joules, a common unit of energy used in the physical sciences.
Most of us think of calories in relation to food. It turns out that the calories on a food package are actually kilocalories (1,000 calories = 1 kilocalorie). The word is sometimes capitalized to show the difference, but usually not. A food calorie contains 4,184 joules. A can of soda containing 200 food calories contains 200,000 regular calories, or 200 kilocalories. A gallon of gasoline contains 31,000 kilocalories.
The same applies to exercise. When a fitness chart says you burn about 100 calories for every mile you jog, it means 100 kilocalories. So when I say calorie, what I really mean to say is kilocalorie.
We all need energy to survive. The number of calories in a food is a measure of how much potential energy that food possesses. A gram of carbohydrates has 4 calories, a gram of protein has 4 calories, and a gram of fat has 9 calories. Foods are a compilation of these three building blocks, so if you know how many carbohydrates, fats and proteins are in any given food, you know how many calories, or how much energy, that food contains.
If you look at the nutritional label on the back of a package and it says160 calories, this means that if we were to pour this into a dish, set it on fire and get it to burn completely, the reaction would produce 160 kilocalories (food calories are kilocalories) or enough energy to raise the temperature of 160 kilograms of water 1 degree Celsius.
Your body burns these calories through metabolic processes, by which enzymes break the carbohydrates into glucose and other sugars, the fats into glycerol and fatty acids and the proteins into amino acids. These molecules are then transported through your bloodstream to your cells, where they are either absorbed for immediate use or sent on to the final stage of metabolism in which they react with oxygen to release their stored energy.
So just how many calories do your cells need to function? Well it differs for everyone. You may notice on the nutritional labels of the foods you buy that the percent daily values are based on a 2,000 calorie diet, but your body might need more or less than 2,000 calories. Height, weight, gender, age and activity level all affect your caloric needs.
There are three main factors involved in calculating how many calories your body needs per day, Basal metabolic rate, Physical activity and thermic effect of food.
Your basal metabolic rate (BMR) is the amount of energy your body needs to function at rest. This accounts for about 60 to 70 percent of calories burned in a day and includes the energy required to keep your heart beating, your lungs breathing, your kidneys functioning and your body temperature stabilized. In general, men have a higher BMR than women. One of the most accurate methods of estimating your basal metabolic rate is the Harris-Benedict formula which is explained in my book‘Get fit Stay Fit’
The second factor physical activity, consumes the next highest number of calories. Physical activity includes everything from making your bed to jogging. Walking, lifting, bending, and just generally moving around burns calories, but the number of calories you burn in any given activity depends on your body weight. Check out my fitness calculators on my site…or the formulas in my book so that you can personalize your calories burned per activity.
The final number of calories your body burns is the thermic effect of food. This is the amount of energy your body uses to digest the food you eat. It takes energy to break food down to its basic elements in order to be used by your body. To calculate the number of calories you expend in this process, multiply the total number of calories you eat in a day by 0.10, or 10 percent.
The total number of calories your body needs in a day is the sum of these three calculations.
So if you take in more or fewer calories than your body burns, you either gain or lose fat. And for every extra 3,500 calories stored by your body you gain 1 pound of fat. If you burn 3,500 more calories than you eat, whether by exercising or eating less, your body converts 1 pound of its stored fat into energy to make up for the deficit.
One thing about exercise is that it raises your metabolic rate not only while you’re huffing and puffing on the treadmill, it continues to function at a higher level, burning an increased number of calories, for about two hours after you’ve stopped exercising.
So does it matter where your calories come from? If you eat exactly the number of calories that you burn and you are only talking about your weight, the answer is no. A calorie is a calorie. A protein calorie is no different from a fat calorie. They are simply units of energy. If you burn what you eat, you will maintain your weight, and if you burn more than you eat, you will lose weight.
But if you do not burn all of the calories you eat and you’re not trying to gain weight, you would probably want your extra calories to come from carbohydrates or proteins instead of fats. Fats are easier to store as fat. Your body expends more energy on the chemical processes that convert carbohydrates and proteins into fats, meaning that some calories are actually burned in the storing process.
If your talking about nutrition, it definitely matters where your calories come from. Carbohydrates and proteins are healthier sources of calories than fats. Although your body does need a certain amount of fat to function properly, like to absorb the vitamins you ingest, an excess of fat can have serious health consequences. A maximum of 30 percent of our daily calories should come from fat. So, if you eat 2,000 calories a day, that’s a maximum of 600 calories from fat, or 67 grams of fat, per day. However, if you strive to get 25 percent of your daily calories from fat it is better. That’s 56 grams of fat per day (500 calories) for a 2,000 calorie diet.
I know you want to get in shape and look great. Whatever your fitness goal…to slim down…gain muscle…tone your arms or flatten your tummy…I’m here to help you accomplish your goals and to improve your fitness level. If you have enjoyed this article and the many other free features on my site, and would like some more comprehensive information such as fitness books and CD’s to aid you in achieving your health and fitness goals, please visit my ONLINE STORE where you will find innovative natural health and beauty products to help you become the BEST YOU CAN BE !