While many fad in diet books slam carbohydrates in praise of protein, there is no scientific evidence to support these claims. The proof of any theory lies in the weight of the scientific evidence. When it comes to claims that pasta is fattening or that the right mix of protein and fat alters metabolism in favor of athletic performance, the evidence is sorely lacking.
Repeatedly, studies show that more Americans are overweight today, not because of quality carbs, but because they eat too many calories and too much fat and refined foods, and exercise too little. (Keep in mind that a century ago the definition of a sedentary lifestyle was one where a person was intensely active for less than three hours every day! Now we praise ourselves if we exercise for 30 minutes three times a week.)
When people lose weight on high-protein or low-carbohydrate fad diets, it’s because they’ve limited their food intake, which means they cut calories. Most fad diets supply about 1,200 calories or less a day; you’d lose weight on any diet when you eat so few calories. Actually, there is nothing new about these high-protein diets. They cycle around about every 20 years, and leave people no lighter in the long-run, but at higher risk for developing kidney stones and osteoporosis.
In contrast, there are 1,000s of scientific studies spanning decades of research showing that diets rich in unrefined carbohydrate foods – from fruits and vegetables to whole grains and legumes – lower your risk for chronic diseases, are the best way to attain and maintain a desirable weight, maximize athletic performance, and help you live longer and healthier. Granted, it is easy to overconsume highly refined foods, many of which contain processed wheat flour. Cutting back on processed junk is the mainstay of any good diet. In contrast, whole grains and starchy vegetables like sweet potatoes remain some of the best foods in the diet, as long as they are minimally-processed and accompanied by low-fat choices.