The dieting industry is a booming business in the United States – $60 billion, in fact, according to estimates. This includes hundreds – if not thousands – of different types of diet programs, consultations, books, guides, plans and much more.

These “fad diets” – like Atkins, South Beach and the Paleo – offer the “magic” promise of quick weight loss, among other dramatic benefits. Individuals often start these diets from word-of-mouth or quick Google searches, but few actually look through the facts to understand how a particular diet does or, more importantly does not meet, their unique nutritional needs.

The problem is that diets can also have dangerous side effects that many weight loss companies fail to mention in their ads. Rapid weight loss can weaken your immune system, starve your body and brain of nutrients and vitamins and actually cause weight gain by slowing your metabolism. And then there is the damage it can do to your heart. Rapid weight loss strains the muscles in your heart, putting you at greater risk for heart disease and heart attacks.

Additionally, the side effects of a crash diet can be even more damaging for someone already at risk for developing an eating disorder. Dieting can cause obsessions about weight loss and shame around food. Studies have found that 35% of “normal” dieters will develop pathological dieting, and 25% of those individuals will develop an eating disorder.

To help you better understand fad diets, I interviewed two experts, Mary Gates, RD, CD-N and Jennifer Buden, MS, RD, CD-N, both dietitians at the Walden Eating Disorder Center at Rockville Hospital, a 30-bed inpatient facility in Rockville, Conn.

What advice would you give someone who is considering a fad diet?
“In general, it’s important to focus on making changes that you can stick to long term. Managing your health and well-being is a journey. There’s no quick fix or short-term solution. Lifestyle changes take time and that’s okay.

For someone who is considering dieting, you should seek the advice of your physician or a registered dietitian, to determine if your goals are appropriate and if so, at what rate you should adhere to the diet.”

Why is it important to consult a professional before choosing a diet?
“It’s important to seek the advice of a physician and dietitian to determine if the diet is right for you. Everyone’s nutritional requirements, health needs, and metabolism are different. Diets are never one-size-fits-all. Professionals can help you determine the safest approach when taking into consideration your health history.”

When obtaining any health information, it’s important to find credible sources and some level of validity. Individuals should ask themselves: is the information based on evidence? Does it include reliable references? When was the information last updated? It’s absolutely okay to verify with your physician that the information is accurate and appropriate for you.”

Why do most people gain back most of the weight lost using a fad diet?
“Fad diets in general tend to be restrictive and difficult to maintain over time. They often limit various foods or food groups essential for adequate energy, vitamins and minerals. This can be potentially dangerous to one’s health.”

I then asked for their take on four different popular diet plans, giving them the name and the description of the diet:

4-Hour Body – Eliminate dairy, sugar, white carbs, whole wheat, fruits from your diet for six days a week, eat whatever you want one day a week.

“This diet poses a lot of risks. Limiting carbohydrates deprives the brain and body of its preferred energy source (glucose). Lack of adequate energy can result in weakness, irritability and poor concentration, among other potential dangers.

This diet is extremely restrictive, resulting in severe nutrient deficiencies. It is impossible to follow long term without serious health consequences.”

Intermittent fasting eg the 5:2 Diet – Eat a normal amount of calories 5 days per week, then restrict to 25% of you caloric needs for two days a week.

“Again, restricting your intake for any period of time can interfere with your mood, as well as the ability to concentrate and function on a daily basis. Fasting for weight loss inadvertently slows metabolism and makes people feel sluggish. This could potentially result in adverse health benefits over time.

The body requires a constant balance of nutrients and energy to perform basic functions such as making the heart beat, lungs expand and food properly digest and metabolize.

This diet is simply not sustainable. What would someone do when they are attending a social gathering on a fasting day? Very quickly, restricting intake interferes with both physical and mental health.”

Mediterranean – Eat fruits, veggies, whole grains, beans, nuts, legumes, olive oil, and flavorful herbs and spices; fish and seafood at least a couple of times a week; and poultry, eggs, cheese and yogurt in moderation.

“The Mediterranean diet is not considered a fad diet and has been followed by countries in the Mediterranean region for thousands of years. This eating pattern has been heavily researched over the years and commended for its health benefits. People living in the Mediterranean region typically have the lowest rates of chronic diseases (heart disease, diabetes, cancer).

This diet emphasizes variety and contains adequate sources of carbohydrates, proteins, fats, vitamins and minerals. This is one eating pattern that can support good health.”

Paleo – No refined sugar, legumes, grains or dairy

“There are a lot of misconceptions with the belief the Paleo Diet replicates the dietary behaviors of our cavemen ancestors. We often forget that our early ancestors had shorter life spans and were purely limited to the foods that grew in the climate where they lived. In addition, carbohydrates were considered staples in some of these early civilizations.

This diet can also be very restrictive, and limits grains which provide essential B vitamins, complex carbohydrates and fiber. For the average person, this diet is not sustainable long-term.”

While it is important to pay attention to the needs of your body, whatever those may be, “fad diets” are rarely effective in improving overall health. Your nutritional intake should rely more on your internal hunger and bodily cues, rather than external rules.

When in doubt, seek a professional opinion. You’re always welcome to email us for advice!

Pat Jones is the Marketing and Professional Relations Manager for Walden Eating Disorder Center at Rockville Hospital. Prior to joining Walden, Pat worked in marketing and admissions for several other mental health agencies in New England. He is passionate about finding appropriate care for patients and their loved ones. Pat spends his time outside of work hiking, fishing and watching LSU football. He lives in Avon, Ct with his partner Lauren, a dog named Zoe and a cat named Mitch.