Can Fad Diets Work?

It seems every week there’s a new sensational diet promising to help you shed pounds quickly.

These diets are often overly restrictive and focus on quick and dramatic results. But do they really help you get to and stay a healthy weight?

AICR takes a look at what some fad diets promise – and actually deliver. Then we’ll help you lose weight for the long term without giving up the foods you love.

The Grapefruit Diet

The claim: Eat grapefruit or drink its juice at each meal so grapefruit enzymes will help you “burn fat” to lose 20 pounds in 12 days.

The facts: At 800-1000 calories per day, most people do lose weight, but it's hard to follow for very long, and there’s no evidence that grapefruit burns fat.

Grapefruit is loaded with vitamin C and fiber, so skip the “grapefruit diet” and instead have grapefruit with breakfast or top a green salad with grapefruit sections.

The Blood Type Diet

The claim: Your blood type - A, B, AB or O - affects your digestive system and therefore what foods you can tolerate. Eating this way leads to health and a lower weight. For example, people with blood type O have to avoid grains, breads and legumes.

The facts: There is no scientific evidence supporting the claims that blood type affects digestion or weight.

The Intermittent Fasting Diet

The claim: You can lose weight and improve health by eating about 500-600 calories two days a week. The other five days, eat what you want.

The facts: Although some early research has shown potential health benefits and weight loss with intermittent fasting, evidence is lacking on the long-term health implications. Plus, eating too many foods like fried foods and sweets, is still unhealthy.

This diet may be challenging to stick with long term and once you stop, the weight will likely come back.

The China Study Diet

The claim: You can lose weight and lower your risk for type 2 diabetes, heart disease and cancer by eating a vegan diet.

The facts: By eliminating all animal foods, many people do eat fewer calories and lose weight. Following a vegan diet long term though, can be difficult and it is challenging to meet recommendations for several nutrients, including calcium, iron and B12.

Research shows you can lose weight and gain the health benefits of plant foods with a diet that includes moderate amounts of animal foods.

The Wheat Belly Diet

The claim: Today's wheat is different from caveman days causing many health problems, like diabetes. So, you eliminate all wheat for life, and most starchy foods, including legumes.

The facts: Cutting out all starches can often lead to weight loss, at least short term. But you also lose some fiber and health promoting phytochemicals like phenols.

There is strong evidence that foods containing fiber, such as whole wheat, protect against cancer. For weight control, do focus on vegetables, fruit, whole grains and legumes.

The Master Cleanse

The claim: Drink the Master Cleanse (lemon juice, maple syrup, cayenne pepper) along with salt water and an herbal laxative tea for 7-10 days for very quick weight loss. It's promoted as a detoxification and cleansing diet, popularized by the singer Beyonce.

The facts: You would lose weight because it is so low in calories, but you'll likely gain it all back (Beyonce said she did). And you may experience dizziness, headaches, constipation and diarrhea.

Excess body fat isn't from toxins or built up waste; it's how the body stores excess calories we eat. This and other detox diets are ineffective for long-term weight loss and can be harmful.

The Atkins Diet

The claim: This diet is all about severely limiting carbohydrates which helps your body burn fat quickly. You can eat plenty of steak, chicken, fish, cheese and fats. You can only eat some non-starchy vegetables.

The facts: This diet can promote quick weight loss especially in it's early restrictive phase, because it is extremely low in calories. A benefit is that you will consume no sugary foods or beverages.

However, the Atkins Diet severely limits healthful plant foods, like whole grains, fruit and some vegetables. These foods leave you feeling fuller so that you’ll eat less, and research shows that a plant-based diet helps reduce risk of chronic diseases, including many cancers.

The New American
Plate Diet

The claim: Eating a plant-based diet will help you lose weight as well as prevent cancer. Build a plate that is 2/3 plant-based foods (or more) and 1/3 (or less) animal protein.

The facts: AICR’s New American Plate is a research supported long-term way of eating. Controlling portion sizes and eating foods that are rich in nutrients but lower in calories will help you feel better, lose weight and prevent many chronic diseases.

We're launching a new program to help you to do just that. Sign up to join others in our New American Plate Challenge.

More on Getting to a Healthy Weight

Calculate your Body Mass Index (BMI)

Read about the New American Plate

Sign up now to participate in the New American Plate Challenge