You know by now that both eating and activity affect your weight. Eating provides your body with the energy it needs, while physical activity burns off calories. So the key to successful weight loss is finding the right ways to balance the calories you take in with the calories you put out. It all sounds so simple – and it really is.
But there’s actually a lot to know. How to track calories in food. How calories are used and stored as fat. What is starvation mode? Can you cut calories too far? What to do about plateaus? This simple, little thing called a calorie can actually seem pretty complicated. Read on to help sort through the mystery.
The Confusing Calorie. The calorie is a measure of energy available to the body. When you eat food, the number of calories it contains is actually the amount of energy units the food provides the body. The calorie is also the measure of energy that your body uses. Your body uses calories for many functions, such as breathing, pumping blood, resting, sitting, working, and exercising. So the calorie is used to measure both the amount of energy contained in foods, as well as the amount of energy your body uses.
The difference between the two is the Calorie Equation. When you eat more calories than you use, the rest is stored as fat and you gain weight. To lose weight, you simply need to use more calories than you eat so your body is free to call upon other energy sources – such as stored fat.
Where Do Calories Come From? There are six classes of nutrients: carbohydrate, protein, fat, vitamins, minerals, and water. Of these six classes of nutrients, only 3 provide calories or energy for the body: carbohydrate, protein and fat:
1 gram of carbohydrate = 4 calories
1 gram of protein = 4 calories
1 gram of fat = 9 calories
Calories are also found in alcohol. Alcohol is not a nutrient because it cannot be used in the body to promote growth, maintenance, or repair. It is a toxin that is broken down as an energy source and can be converted into fat.
1 gram of alcohol = 7 calories
How are Calories Used and Stored? The function of each calorie-providing nutrient is different, but the end result of excessive intake is the same…FAT STORAGE.
Carbohydrate is broken down into glucose for immediate energy needs; the surplus is stored as glycogen for long-term energy needs and brain function. However, after the glycogen stores are filled, the excess carbohydrate is stored as FAT.
The nutrient Fat is initially broken down and used for its primary functions, such as providing cell structure. However, any excess fat fragments will be reassembled and stored in the FAT cells.
Protein will also encounter the same fate. Once protein has met immediate energy needs and provided the body with other building and repairing functions, the excess will be converted into FAT and stored away.
All foods supply energy or calories. However, some provide more calories than others. No single food or class of food is “fattening” by itself. When the calories provided in food are not needed by the body, the excess is stored in the body in the form of fat, no matter what food the calories came from. And while the storage of most cells is limited, fat tissue is able to store an unending amount of fat.
How Many Calories Do I Need? Your energy needs take precedence over all other body functions. For an adult, there are three factors that determine your total energy requirements:
Basal Energy Requirement. This is the minimum amount of energy needed by the body at rest in the fasting state. It includes basic body functions such as respiration, cellular metabolism, circulation, gland activity, and body temperature control. It is affected by such things as age, gender, pregnancy, body composition, nutritional status, sleep, climate, and fever.
Physical Activity. The amount of calories needed for physical activity depends on the type of activity or work, the intensity and the duration. To learn calorie levels for different activities, check out the Calorie Lookup tool in the Fitness Resource Center, or print the Calories Burned Chart from the Printable Resources page.
Specific Dynamic Action of Food. This is the amount of calories needed to manage food intake and includes digestion, absorption, and metabolism of food.
Balancing the calories you take in with those you put out is the safest, healthiest way to control your weight – for the next two weeks, or the next 20 years. It takes about 3500 calories to make one pound of fat. So to lose one pound, you can:
a) Burn 3500 excess calories (if you have a few hours to kill)
b) Eat 3500 fewer calories (starvation diet, anyone?)
c) A combination of exercise and diet (the best option)
For example, to lose one pound in a week, you could simple create a calorie deficit of 500 per day (7x500 = 3500). That could be as simple as cutting out one donut (280 calories) and jogging for 25 minutes (240 calories) each day.
Paying attention to both sides of the Equation actually makes it easier to lose weight than relying on one or the other, and is much easier on your body.
The SparkDiet Set Up process used scientific calculations to determine your current calorie needs as well as calorie and fitness goals to promote weight loss based on the information you provide. By using the meal plans, nutrition tracker and calories-burned tracker, you are able to monitor your calorie intake and output.
Starvation Mode. There is a common misperception that to lose weight, the lower the calories, the better. Ironically, the key may be eating more calories. You can actually hurt your body's ability to lose weight by going too low. Here's why. The body has a protective mechanism. When calories drop too low (we recommend a minimum of 1,200 for women and 1,500 for men) the body reacts as if it is starving and tries to conserve energy. It will lower your metabolism, conserve calories and fat, and you will not burn calories as quickly. This results in a slower weight loss or even no weight loss. This is what's know as "Starvation Mode."
When calorie intake falls below 1,200 to 1,500 calories a day, it is also extremely difficult to follow a balanced diet and obtain all the nutrients that are needed by the body to stay strong and energetic and prevent disease. These very low calorie intakes can also lead to other health problems such as eating disorders, gout, gallstones, and heart complications. For these reasons, the SparkDiet strongly suggests not going below 1,200 calories daily for women and 1,500 calories daily for men.
Muscle Power. Fat tissue lowers the rate at which one burns calories, because fat tissue requires less oxygen and is very inactive. On the other hand, muscle is a more physically and metabolically active tissue. It therefore burns more calories than fat. Through exercise, especially strength and resistance exercise, you can decrease the amount of fat in your body and increase the amount of muscle. This will then help you burn more calories each and every day, even when you’re not exercising.
Muscle also weighs more than fat. Near the beginning of your program, you may gain some weight after strength exercising. This is perfectly normal. As the composition of your body changes from fat to muscle, the muscle will help burn off that remaining fat at a faster rate, uncovering your lean, fit muscles.
On The Dreaded Plateau? Hitting a plateau during a weight loss program is normal (though it can still be frustrating). Your body requires fewer calories to function as your weight decreases. It needs time to adjust to all the healthy changes that are occurring due to the weight loss. So continuing to follow the same eating and exercise patterns won’t work forever.
Everyone’s body will adjust differently. To jump-start your metabolism and break out of the plateau, you may need to select a different form of exercise to stimulate other muscle groups to become more active. Do not become discouraged; this may take several weeks or months. Stay focused on all the positive things you have accomplished. Your goal during plateaus is to try not to gain any pounds back. Get energized with a brisk walk. Add on a little jogging or running. Try a new piece of equipment. Test out a strength training routine. Try a new activity like dancing, rollerblading, or cross-country skiing. Start taking the stairs at home and work.