In a time when everyone is obsessed with everything instant, people are likely to fall into fad diets that promise weight loss in an unrealistically short period of time. Shedding a few pounds in a fast and easy way is too attractive, that even those who are health-savvy cannot resist taking a second look.
These kinds of diet called fad diets come in all forms and methods - juice-fasts, no-carb, all-fat diets, to name a few, all promise quick results if only you follow their strict instructions.
Fad diets usually do not follow healthy eating habits that are essential for keeping good health.  These kinds of diet may be harmful to your health. These are usually too low in calories which means that you won’t get enough energy to do the things you need to do, and you won’t get all the nutrients your body needs to function properly.
Spotting a fad diet.
“It seems to be human nature to be attracted to fad diets, which promise quick and easy results,” says Allen Knehans, Ph.D., chair of the department of nutritional sciences at Oklahoma University Health Sciences University in Oklahoma City. Spotting a fad diet takes a bit of effort because, as Knehans acknowledges, “there is no standard definition of a fad diet.” 
However, a fad diet shares some, or all, of the following characteristics: 
- Promises a quick fix
- Promotes 'magic' foods or combinations of foods
- Implies that food can change body chemistry
- Excludes or severely restricts food groups or nutrients, such as carbohydrates
- Has rigid rules that focus on weight loss
- Makes claims based on a single study or testimonials only.
- Gives you nutrition advice that is based on testimonials rather than scientific evidence.
- Does not encourage physical activity.
In addition, fad diets are usually popular only for a season, or for a short period of time.
Effective, at a cost.
Usually, fad diets deliver their promise of losing weight quickly. Many fad diets cause you to drop a few pounds because of the unhealthy calorie reduction or water weight loss.
“The fad diets succeed at jolting you from the grind of mindless snacking, eating junk food on the run, and all the calorie and fat-packed extras like whipped cream in the cappuccino, or grabbing a slice of pizza on the way home from work. Just making these lifestyle adjustments is usually enough to see some weight loss,” explains nutritionist Judy Penta, BS, a certified holistic health counselor and personal trainer with Patients Medical in New York City.
However, this comes with a price. While you enjoy the benefits of losing weight fast, your overall nutritional makeup is at risk. Unfortunately, many fad diets do not meet the nutritional needs of most people. Here are some signs that a fad diet is not healthy for you:
- Muscle cramps
- Severe constipation or diarrhea
- Mood changes
- Constant hunger
In addition, there are also some psychological consequences to fad dieting, Penta adds. Achieving your goal weight rapidly also makes you quickly revert to your old eating habits. This will ultimately result in regaining the weight you lost.
Quickly losing and gaining weight or ‘yo-yo dieting’ is bad for your body. It puts you at risk of various heart problems as it forces your heart to work at different paces with no time to adapt. As you gain weight, the heart works much harder becoming larger and stronger. Meanwhile, when you suddenly lose weight, the heart pumps too hard for a smaller body. 
In general, it’s best to steer clear of these fad diet plans that are not healthy and don’t result in long-term weight loss. Subscribe to a healthy diet that is safe and effective not only in the short-term. It’s always best to consult your doctor if you want to lose weight.