Fad Diets

A fad diet is a diet that promises quick weight loss through what is usually an unhealthy and unbalanced diet.



Fad diets that are restricted to certain foods may work, but most are boring or unappealing. This can make them difficult to follow on a long-term basis. And some fad diets can actually be harmful to your health.

How to Determine Fact from Fad


To determine if a diet is a fad diet, ask yourself these questions:

  • Does the diet promise quick weight loss?

  • Does the diet sound too good to be true?

  • Does the diet help sell a company’s product?



If you can answer “yes” to any or all of these questions, the diet is probably a fad diet.

Examples of Fad Diets

High-protein diets

These diets propose that you eat large quantities of protein (meat, eggs, etc.) to lose weight and build muscle. Regular physical activity and weight training build muscle strength, not eating large quantities of protein.

This type of diet can actually be dangerous. If you exceed the amount of protein your body needs daily, you put a strain on your liver and kidneys. The early weight lost with this diet is usually due to water loss, not fat loss.

Diets that focus on protein-rich foods may be missing specific nutrients and adding fat and calories to your diet.

Liquid diets

Liquid diets cut out substances that may be beneficial to the body.

For example, phytochemicals (FY-toe-KEM-uh-kals) are plant substances (found in vegetables and fruits) believed to protect against disease. In addition, the effects of a liquid diet may be only temporary. Once you return to eating regular foods, you usually put the pounds right back on.

Grapefruit diet

This diet proposes that eating only grapefruit will help you shed pounds. But any diet based on one food is much too restrictive to be healthy.

Usually, this type of diet is too low in calories and is missing needed vitamins and minerals.

Juice or broth fasts

Some dieters try to lose weight by drinking only juice and/or broth for a period of time.

Fasting (not eating solid food) for a long period of time can lead to dizziness and fatigue. In addition, your body reacts to starvation by lowering your metabolic rate (the rate at which your body burns calories). This means your body is burning fewer calories.

Food-combining diets

Some diets propose that a certain combination of foods will help burn calories faster. There is no scientific evidence to prove that the body processes certain combinations of foods any differently than random ones.

Some of these types of diets are low in protein and vital nutrients, and others may cause diarrhea.

Crazy for cabbage

This all-cabbage fad diet helps dieters shed mostly water weight. Once the diet is stopped, the weight is usually regained. It may also cause gastrointestinal problems and light-headedness.

Potential problems with fad diets

Poor long-term weight control

Most fad diets promote a “quick fix” and don’t teach healthy eating plans. They tend to be restrictive, boring, and difficult to follow over the long term. Once the weight is lost, a dieter often returns to old eating patterns and habits, causing him or her to regain weight.

Increased risk of chronic disease, like heart disease, cancer, high blood pressure, and osteoporosis

Many fad diets restrict or eliminate fruits, vegetables, dairy products, and whole grains. These foods are loaded with nutrients that are thought to help prevent many chronic conditions.

In addition, diets that are too high in protein may cause an increase in calcium loss, leading to osteoporosis.

Reduced athletic performance

Diets that significantly restrict carbohydrates increase symptoms of fatigue and decrease body energy supplies and endurance. In addition, low carbohydrate diets cause a loss of fluid and electrolytes.

Your body needs carbohydrates for energy. Carbohydrate stores are tied to fluid in your body. When you don’t eat enough carbohydrates, your body pulls from your stores, also pulling fluid and electrolytes in the process. Your body then gets rid of fluids and electrolytes. This can cause low blood pressure and decreased performance.

Kidney stones and gout

Diets that are high in protein and low in carbohydrates often lead to the formation of uric acid and calcium oxalate, causing kidney stone formation and gout.


A diet that is low in carbohydrates puts your body into ketosis, a condition that is unnatural.

Ketosis most often occurs in starvation, but it can also occur if you don’t eat enough carbohydrates. Without adequate carbohydrates for an energy supply, fat becomes the primary energy source and ketones become the means of transportation. You may notice “keto breath” or a funny smell to your breath.

Talk to your doctor or a registered dietitian before beginning any diet or changed meal plan. Remember that fad diets have a low chance of success and may have harmful side effects.







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