While most of us know that consuming excessive amounts of fat will make us fat, we don't all understand exactly why this is true. To implement a successful weight management program, you need a good understanding of fat and why this nutrient makes us fat.

The amount of energy a particular food has depends on the quantity of fat, carbohydrates, and protein it contains. Food energy, both in its consumption and expenditure, is measured in terms of calories. Foods are either made up of fats, protein, carbohydrates, or a combination. A food that contains mostly fat will contain more than twice the calories than a food containing mostly carbohydrates and/or protein. For example, compare a serving of low-fat yogurt to a serving of nonfat yogurt--the low-fat yogurt has quite a few more calories than the nonfat variety because every gram of fat has more than twice the calories of a gram of protein or carbohydrate. Fat contains 9 calories per gram; protein and carbohydrates yield only four calories per gram. Therefore, it is important that you move towards replacing foods high in fat with foods higher in protein and complex carbohydrates.

No more than 25 percent of your total calories should come from fat, fewer than 10 percent from saturated fat, the most damaging form. A recent study of 23 lean men and 23 obese men found little difference in the total number of calories each group consumed. But the obese men consumed, on average, more than 33 percent of their total calories from fat, compared with 29 percent for the lean men. Because the body converts dietary fat into body fat more easily than it converts protein and carbohydrates into body fat, the obese men were storing more fat even though both groups consumed the same total number of calories.

During the process of converting protein and carbohydrates to fat, your body uses them as energy and burns more than a quarter of their calories; it takes more energy (calories "burned") to convert carbohydrates and protein into body fat than it does to convert dietary fat into body fat. Thus, more carbohydrate and protein calories are used and fewer are stored as fat. Dietary fat, on the other hand, goes straight into storage, with very few calories being used. For example, John consumes 2,000 calories a day of which 40 percent come from fat. If John replaces half of the fat calories (20 percent of total calories) with calories coming from complex carbohydrates, less food will be converted to body fat even though the total number of calories consumed has not changed.

It is important to note that when that 20 percent of the 2,000 calories from fat now comes from carbohydrates (or protein), you consume a lot more food, since each gram of carbohydrate or protein contains less than half as many calories per gram. Therefore, when you begin to decrease the amount of fat in your diet and replace it with carbohydrates and protein, even if you still consume the same amount of food as before, you will be consuming a lot fewer calories.

If dietary fat were easy to control, most "diets" would probably succeed. Even with the recent explosion of low-fat and nonfat products, people generally still eat too much fat. The reason is simple: We have grown up loving fat, and we are accustomed to its taste and texture. Although most people do not usually crave fat as they do sugar or salty foods, we do have a strong taste preference for fat. Fat is responsible for the flavor and texture of many of our favorite foods: meats, cheese, dressings, sauces, creams, desserts, etc.

Because a high-fat diet increases fat storage and yields more than twice the amount of calories, the most effective way to reduce body fat is to concentrate on reducing your daily fat intake. Even if you do not consciously lower your total caloric intake, making the switch to a low-fat diet will most likely result in fat loss. However, attempts to suddenly restrict high-fat foods when you still have a strong preference for them causes feelings of deprivation which may, in turn, cause a higher intake of fat than normal. Deprivation is part of the "diet" process, and one of the main reasons it is doomed to fail. It is very important to make gradual, healthier changes to the foods you enjoy. Drastic changes backfire. When people base their food choices on the number of calories consumed and a "foods allowed/not allowed" list, the focus is on numbers rather than satiety and enjoyment of the foods' taste and texture. This often negates any positive effect the original focus on choosing low-fat foods may have had. Simply counting calories and grams of fat does not make for a permanent healthy lifestyle change. If tastes do not shift to enjoying foods lower in fat, this quickly becomes too restrictive and normal eating habits resume.

I'm not saying that you should avoid counting grams of fat altogether. The way to lower fat in your diet is to become a fat-conscious eater--and this requires that you know the amount of fat in each food. However, instead of counting fat grams and deciding if it is a "good food" or a "bad food," try to balance the foods you are eating so that you average 25 percent or less of your total calories from fat each day. It's okay to have a piece or two of high-fat pizza (pizza can be low-fat) if you are truly hungry and craving it, as long as you balance that out with low-fat foods at other meals soon after. What's crucial is to learn how to make small healthier changes. Consume fat in moderation by balancing higher fat foods with lower fat foods.

You should now have a better understanding of fat and why excess consumption of this nutrient makes us fat. Your greatest challenge, however, is not learning new low-fat shopping or cooking techniques. Nor is it remembering how to calculate fat percentages or what to say to the waiter to reduce the fat in your restaurant meal. The greatest challenge facing you at this moment is deciding whether you are willing to make a change--to make small, gradual changes to the foods you love.

Sure, there is plenty of work to be done, but it really doesn't matter how long this new process takes. If you allow changes to take place over several years, your body will adjust comfortably, and you will be more likely to maintain the healthy lifestyle permanently. When you begin achieving improvements in energy and physical and psychological performance, the fun and excitement you experience will make the change well worth the effort. Action creates motivation! Good luck: I hope you enjoy all the wonderful benefits of a healthy, active lifestyle.