The nutrition industry makes its living by operating on a pendulum--for a time, they espouse the virtues of low-fat diets while condemning low-carb diets. As the pendulum swings the other way, suddenly low-carb diets are king, while low-fat diets are cast into exile. The best course for dieters is to ignore the trends, and focus on making an informed decision. Although low-fat, high-carb diets have been recommended for decades, they are not without risks.
Risk 1--Hormone Imbalances
Fat was long considered the enemy of dieters, but the simple truth of the matter is--fat does not make you fat. Your body needs fat to fuel the body's hormonal systems, including the production of sex hormones like testosterone. Normal testosterone levels are necessary for a healthy sex drive, strong energy levels, and the retention of lean muscle mass. Dieters sticking to a low-fat regime sometimes skirt the minimal acceptable levels of fat intake, playing Russian roulette with their hormone levels.
Risk 2--Inefficient Dieting
No one wants to be stuck on a diet forever. Prolonged dieting is a psychologically draining event. The longer it takes for your diet to produce results, the more likely it is that you will just resign yourself to your "fate" and give up. Thus, it pays to use the most efficient tool for the job. And it is generally accepted that low-carb diets produce superior weight loss results.
Risk 3--Inadvertant Cheating
Whereas the rules of a low-carb diet are clear-cut and binary--stay below X grams of carbs per day while eating whatever high-fat and high-protein foods you want--the rules of low-fat dieting are slightly more murky. This leads to inadvertent cheating whereby dieters blur the line between healthy carbs, like fruits, veggies, oats, and whole grains, and unhealthy carbs (i.e. everything else--processed grains, starches, white bread etc.), rationalizing the departure from the dietary recommendations so long as their total fat intake remains within a certain tolerance. This makes low-fat dieting the nutritional equivalent of skating on thin ice--it is too easy to accidentally fall in.
