Successful weight loss is defined as losing weight and keeping it off for at least five years. This can be accomplished by making positive changes to both eating habits and physical activity patterns. Fad diets will not result in long-term weight loss because these diets do not promote healthy and sustainable diet and lifestyle habits.
Food-specific fad diets rely on the myth that some foods have special properties that can cause weight loss or gain - but no food can. These diets don't teach healthful eating habits; therefore, you won't stick with them for very long. Sooner or later, you'll return to your normal eating habits and gain back all (if not more) of the weight you lost while on a fad diet.
The popular high-protein, low-carbohydrate diets are based on the idea that carbohydrates are bad, that many people are "allergic" to them or are insulin-resistant, and therefore gain weight when they eat them. The truth is that people are eating more total calories and getting less physical activity, and that is the real reason they are gaining weight. These high-protein, low-carbohydrate diets tend to be low in calcium and fiber, as well as healthy phytochemicals (plant chemicals). Some authors of these fad diets advise taking vitamin-mineral supplements to replace lost nutrients. However, supplements should only "bridge the gap" in healthy eating and should not be used as a replacement for nutrient-rich foods.
Also, the authors of high-protein, low-carbohydrate diets advocate taking advantage of ketosis to accelerate weight loss. Ketosis is an abnormal body process that occurs during starvation due to lack of carbohydrate. Ketosis can cause fatigue, constipation, nausea, and vomiting. Potential long-term side effects of ketosis include heart disease, bone loss, and kidney damage.
How can you spot a fad diet?
Weight-loss advice comes in literally hundreds of disguises. Most often the "new" and "revolutionary" diets are really old fad diets making an encore appearance. Examples of fad diets include those that:
tout or ban a specific food or food group
suggest that food can change body chemistry
blame specific hormones for weight problems
Ten Red Flags That Signal Bad Nutrition Advice:
Recommendations that promise a quick fix
Dire warnings of dangers from a single product or regimen
Claims that sound too good to be true
Simplistic conclusions drawn from a complex study
Recommendations based on a single study
Dramatic statements that are refuted by reputable scientific organizations
Lists of "good" and "bad" foods
Recommendations made to help sell a product
Recommendations based on studies published without peer review
Recommendations from studies that ignore differences among individuals or groups