The Truth about Fad Diets

The Truth about Fad Diets

Fad diets aren't sustainable for long term weight loss. Here's why...

According to last year’s New York Times expose, NBC’s The Biggest Loser has made quite an impression on weight loss fanatics across the country. Despite the irony of its success (a show that begs you to sit on your couch while you watch other people get in shape? Really?), season seven reportedly captured an audience of greater than 10 million each week. And over 200,000 people apply to be contestants on the show each season… for only 22 spots!

Unfortunately, Loser’s success statistics aren’t quite as impressive as its Nielsen ratings. Despite the hundreds of pounds lost on the show each season, at least 50% of contestants regain the weight and then some. Sooo getting on the show is more competitive than getting into Harvard, and your chances of keeping the weight off are less than ½? What is going on here?? The answer: Very low calorie diets.

How do they work? Technically speaking, very low calorie diets (VLCDs) allow a caloric intake of <800 calories/day with the goal of rapid weight loss. For all you science nerds, the idea is similar to that of a low-carbohydrate diet. Because of restricted energy intake, your body does not have enough glucose to burn for fuel. As a backup plan, you start to burn fat for energy through a process called ketosis. And Voila! Weight loss.

Who should use them? People who are moderately-severely obese, and only under strict medical supervision. Because of the nutritional deficiency of such a restricted diet, patients are prescribed meal replacements that attempt to replicate the nutrients found in real foods.

What are the benefits? In those that are morbidly obese, the diet can be motivating because it promotes weight loss of about 3-5 pounds/week. It’s thought that the possible complications and side effects of the diet are outweighed (haha) by the health benefits of weight reduction.

Are they safe? Short answer, no. VLCDs, like other fad diets, are incredibly unsafe, and those that are put on the diet are closely monitored through biweekly electrocardiograms (to make sure your heart is still functioning properly) and blood work (to monitor your electrolytes, vitamins and minerals, transport proteins, etc). Common complications and side effects include: irregular heartbeat, weakening of the heart muscle, electrolyte imbalance, muscle cramping, high uric acid (causing gout and kidney stones), dehydration, hair loss, decreased bone density… am I starting to sound like a pharmaceutical advertisement? And if that isn’t enough, these diets can cause some serious damage to your noggin. The brain thrives on glucose (click here for more on the glycemic index), and simply cannot use energy manufactured from fat or protein. To make matters worse, the ketone bodies produced during ketosis are acidic and potentially lethal! An overload of ketones in the presence of starvation can lead to altered mental status, coma, and even death.

What is with the weight regain? For one, a lot of the weight you are losing comes from fluids. Basically, sodium retains water in the body, and by cutting back on the processed and high salt foods, you are reducing your sodium intake and losing “water weight.” In addition, the stored form of glucose in the body contains about 3 parts water to 1 part carbohydrate. When these stores are depleted and used for energy, the water surrounding them goes with it. So the second you start eating normally, you will “gain weight” in the form of fluids. These fluid changes can also account for normal fluctuations of up to 5 pounds per day under a normal diet. No, it wasn’t that burger you ate the night before, just some good old-fashioned hydration.

Secondly, through your crazy restrictions, you’ve caused your body to burn muscle mass and slow metabolism. The second you start eating normally again… WHAM! The pounds start flying back on, and your body composition has changed to more fat and less muscle. Do you really want to endure hair loss and kidney stones only to come back fatter than you started??

Finally, these diets don’t promote sustainable weight loss because they are simply unrealistic…and this is true for ALL of the gimmicky diets on the market. I know you’re thinking that you are different, and that you’ll lose the weight and keep it off, but trust me, the stats are not with you on this one. For prolonged weight maintenance, health professionals do not recommend eating <1200 calories/day, and seriously advocate for manageable lifestyle changes. If you are someone who needs rules to keep your diet in check, please steer clear of regimens that cut out major food groups (low-carb, low-fat, raw foods, paleo, even veganism) and try working on a few restrictions that will change your eating behaviors instead.

Here’s one for the road, taken from Michael Pollan’s ever-charming Food Rules:

#39 Eat all the junk food you want as long as you cook it yourself.
There is nothing wrong with eating sweets, fried foods, pastries, even drinking soda every now and then, but food manufacturers have made eating these formerly expensive and hard-to-make treats so cheap and easy that we're eating them every day. The french fry did not become America's most popular vegetable until industry took over the jobs of washing, peeling, cutting, and frying the potatoes -- and cleaning up the mess. If you made all the french fries you ate, you would eat them much less often, if only because they're so much work. The same holds true for fried chicken, chips, cakes, pies, and ice cream. Enjoy these treats as often as you're willing to prepare them -- chances are good it won't be every day.

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About the Author

Alyssa grew up in New Hampshire and is a lover of any activity that involves mountains (especially the Greens and the Whites!). She speaks Mandarin Chinese and Japanese and lived in both countries as an undergrad (which partially explains her love for Beijing eggplant, lychee, and anything green tea flavored). Currently, she lives in New York City and is working on her master’s degree in public health nutrition at NYU. For the past year, she has been working at NYU School of Medicine’s Center for Immigrant Health, and last fall was awarded the Gstalder Memorial Scholarship for her research and service in minority health. Active in the Greater New York Dietetic Association, Alyssa is working with student members to create a low-literacy cookbook and nutrition guide for cancer patients, which she hopes to have translated into Chinese and Spanish. Before getting into nutrition, she spent time working for several environmental groups, including The Nature Conservancy in Yunnan, China, the Missouri Botanical Gardens in Madagascar, and the Green Mountain Club on The Long Trail in Vermont. Alyssa was recently accepted to a dietetic internship program at the Veteran’s Administration Medical Center in the Bronx, where she will begin work in the fall.