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Fad Diets

MAC Nutrition Team - Tuesday, July 24, 2018

Fad Diets: Are they really worth the hype? MAC Registered Dietitian, Louisa Paine gives us her take!

It seems like just about every time you open your computer, read a magazine, or look at your smartphone, another diet is trending. These popular diets gain interest because they often make lofty promises to help you lose weight and feel better. But, the truth is, most fad diets don’t help much at best, and are harmful at worst. Below, we discuss some of the fad diets that are popular right now.

Paleo Diet

The premise of the paleo diet is: don’t eat anything your Paleolithic-Period ancestors didn’t eat. According to the paleo diet, this means avoiding all grains and legumes, and any processed foods. The paleo diet emphasizes red meat, poultry, fish, eggs, produce, and nuts. While it’s an attractive idea to eat what our ancestors ate, there are some holes in the paleo argument. First, it is not certain what our Paleolithic ancestors ate, and recent evidence indicates that humans ate grains before they started cultivating crops. Also, humans have evolved since the Paleolithic Period, alongside some of our more modern crops. Humans who lived in the Paleolithic Period had an average life expectancy of 33 years, while populations today who eat plenty of whole grains and legumes tend to have the longest and healthiest lives. The diet’s uninformed distinctions between what is and isn’t allowed, encourage unnecessary restriction.

Ketogenic Diet

The ketogenic diet proposes that if you get your body into a state of ketosis, you will lose weight and have more energy. Ketosis means that the body is running on fat instead of carbohydrates. Proponents of the ketogenic diet say that running on fat helps them avoid any spikes or dips in blood sugar levels, which helps them slim down and fight mental fog. In order to get your body into ketosis, you have to eat mostly fat with a very low carbohydrate intake. This means filling up on high-fat foods such as red meat and oil, eating only as many vegetables as the carbohydrate limit allows (vegetables are carbs after all!), and avoiding fruit, legumes, and whole grains, which are all high-carbohydrate foods. Other than in some cases of epilepsy, there is no research-backed reason to follow the keto diet. Eating high saturated fat foods and limiting fruit, whole grains, and legumes are the opposite of what research shows to be the optimal diet for a longer lifespan and health span.

Raw Food Diet

The raw food diet posits that eliminating all cooked food will make you healthier because, it claims, cooking food destroys nutrients. People on the raw food diet fill up on fruits and vegetables and heat food only up to 104-118 degrees Fahrenheit. Because all food is raw, legumes, grains, and animal products are avoided, and the bulk of the diet is generally made up of fruit. While eating more fruits and vegetables and reducing animal products is usually a good idea for health, no research supports the idea that the food must be raw. In fact, following a strictly raw diet seems to make getting enough calories a more expensive and time-consuming process, and sets people up to be at risk for certain nutrient deficiencies. Including plenty of raw fruits and vegetables in your diet helps you fill up on nutrient-dense foods, but cooking some produce helps to release certain nutrients. Eating a variety of cooked and raw produce seems to be the better answer, as well as including cooked whole grains, legumes, and lean protein for their proven health benefits.  

Gluten-Free Diet

A lot of people are going gluten-free these days, claiming the diet helps them lose weight and feel better. Gluten is a protein that is found in some grains, including wheat, barley, and rye. While some people have to follow a gluten-free diet due to an allergy, sensitivity, or celiac disease, most people don’t have any problems with gluten. For those people, arbitrarily cutting it out of the diet robs them of a variety of beneficial whole grains. No research supports the idea that gluten is unilaterally unhealthy for humans to consume, but research does support the fact that whole grains (including gluten-containing whole grains) are good for us.


There are a lot of cleanses out there, from the “Master Cleanse” to juice cleanses. While these cleanses are tempting, claiming to help you lose weight and release toxins from the body, there really is no clinically-validated reason to do them, and there are a lot of reasons not to do them. Drinking a very low-calorie diet of only juice for a week may cause your body to flush out water, losing water weight, but as soon as you start eating normally again, all that weight will come right back. Cleanses tend to be low in calories and restrictive in nutrients, and are therefore dangerous to do for an extended period of time, setting you up for muscle loss, nutrient deficiencies, and electrolyte imbalances. Although these cleanses supposedly rid the body of toxins, research does not show that this is true. In fact, the liver detoxifies the body on a regular basis, rendering these cleanses useless.

Overall, popular diets aren’t worth the hype. Cutting out entire food groups can lead to weight loss due to calorie restriction, but these diets, in addition to being unhealthy and dangerous in some cases, are extremely hard to stick to. So, when people inevitably stop the diet, the weight comes right back. The best weight-loss diets are the ones you can stick to. Instead of doing the next fad diet, try this: eat a variety of whole foods, including plenty of fruits, vegetables, whole grains, legumes, nuts and seeds, and lean protein; listen to your hunger and fullness cues so that you are eating adequate, sensible portions; and move your body purposefully on a regular basis in a way that you enjoy and that makes you feel good. And, as always, reach out to the Mount Auburn Club registered dietitians for help and guidance.

This month's blog contribution comes from Louisa Paine, Registered Dietitian at The Mount Auburn Club.

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The information presented here is for general educational purposes only and is not intended to diagnose, treat, or prevent any disease or health condition. As always, please speak with your registered dietitian regarding any dietary modifications or nutrition-related questions.