Not all calories are alike
Despite all the advances in nutritional science, most people still believe that losing weight is merely a matter of eating less food. Even a lot of doctors believe it and they, of all people, ought to know better! But in truth, many overweight people eat less than thin people – they just eat the wrong things.
Of the three main categories of nutrients – protein, carbohydrates and fat – it’s the fat that contains the most calories. Protein and carbohydrate contains four calories per gram; a gram of fat, on the other hand, contains nine calories. So while fat is an important nutrient for many reasons, keeping your hormones regulated, your skin and hair healthy, and giving you a feeling of satiety when you eat, it also provides over twice as many calories as protein and carbs. And what foods are the highest in fat? Animal foods.
Plant foods, though, are rich in complex carbohydrates, so you can eat more food while ingesting less calories, making you feel fuller and more satisfied. Naturally, you can gain weight while eating carbohydrate-rich foods – remember that excess calories, no matter what their source, are stored as body fat. But studies have shown that, while people eating low-fat, high-carb diets eat more than people on higher fat diets, they’re eating less calories! In a study at Cornell University, people who ate a diet restricting their fat intake to 20 to 25 percent of their calories ate more food than the subjects eating a diet of 35 to 40 percent fat, but never ate as many calories as the high-fat group.
But there’s more to the story than just calories. While doctors and nutritionalists have always advised that dieting is strictly a lower-your-calories endeavor, current research is revealing that it’s far more complicate than that. The way the body uses the calories from protein, carbs and fat varies depending on the calories’ source. The human body is designed to store energy from fat and proteins while it burns carbs for immediate energy. We’re just not meant to store carbohydrates – for every 100 calories that you eat, 23 of them are burned just converting the carbs to usable energy! The fat we eat is a double-whammy – not only are there more calories per gram of fat, only three of every 100 calories are burned during conversion, meaning that it’s later to burn as energy and stored as excess body fat more easily.
The nature of carbohydrates, that they’re the first type of energy that our body turn to, makes it actually difficult to store carbs as fat. In a 1991 clinical study, only 2 percent of the calories eaten by subjects were converted into fat. So while calories are important, it’s the fat calories that are best cut back on.
Now, it’s also possible to lose weight on a high protein, low fat diet, but there are reasons why it’s a bad idea to do so. For one thing, it isn’t easy – the whole foods highest in protein are animal foods, so they’re also high is fat. Perhaps you’ve tried one of these diets in the past and discovered that eating scrambled egg whites, skinless chicken breasts and dry, broiled fish gets very boring, very quickly. But another reason to steer clear of high protein diets is the difficulty, discussed in an earlier chapter, that you body has processing protein. Too much protein overtaxes your kidneys, and it builds calcium deposits in your bones and urinary tract. So the best overall weight-loss plan is one that gives you energy from healthy, complex carbohydrates from plant sources.
