The Health Effects of Alternative, Fad Diets

Diets promoted as quick fixes for weight loss and better health may seem worth a try. But fad and alternative diets can have unexpected and unhealthy risks.

There’s no doubt what you eat can impact your health and how you feel. Likewise, how much you eat — or don’t eat — affects your weight. Science backs those commonsense facts. But it’s not always so easy to recognize whether claims about fad diets are true. At first glance, they may appear to be logical and based on science, too.

Unfortunately, many alternative fad diets are based on dubious or sparse evidence and even outright pseudoscience. What’s more, promoters of such diets rarely mention any health effects that may be worrisome and even dangerous.

Some alternative diets do have research behind them and can be helpful — but that doesn’t mean they are right for everyone. They can have side effects and potential risks, too.

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It’s no surprise many diets touted in books, on the internet, and on talk shows as “quick fixes” are popular. After all, about one in three adults in the U.S. is overweight, and more than 40 percent are obese, according to the Centers for Disease Control and Prevention (CDC).

Many common, chronic health problems, including type 2 diabetes and high blood pressure, are also often linked to poor diet and being overweight.

So, when you hear or read glowing claims about a diet, it’s tempting to try it, hoping you’ll drop excess pounds, boost energy, and improve health. Before you change how you eat, however, and possibly spend your money on diet-related supplements and other products, you should investigate the health effects of alternative fad diets.

Are detox and cleansing diets helpful — or harmful?

Often promoted as ways to remove toxins from your body and lose weight, detoxification and cleansing diets typically involve drinking only juices or protein drinks, or eating only certain foods for a period of time, often while taking specific supplements. Using enemas, laxatives, or colonics (also called colon hydrotherapy) and spending time in a sauna can be part of a detox regime, too.

Very few studies have looked at detoxification diets and programs. According to the National Center for Complementary and Integrative Health (NCCIH), a review of the research conducted so far shows detox diets can produce initial weight loss. The NCCIH adds, however, that you are likely to gain the weight back — and maybe even more pounds — once you resume your regular diet.

There are also safety concerns about detoxification diets. The U.S. Food and Drug Administration and Federal Trade Commission initiated action against companies selling detox diet products that contained illegal and potentially harmful ingredients or were marketed using bogus health claims.

Consider these health warnings about detox and cleansing diets from the NCCIH:

• Some juices used in cleanses aren’t pasteurized and may contain harmful bacteria that can sicken young children, elderly people, and those with weakened immune systems.
• Juices in detox diets often are made from vegetables like spinach and beets, which contain high amounts of oxalate. The natural substance binds to calcium. Drinking large quantities of oxalate-containing juices during a “cleanse” raises your risk for kidney problems, especially kidney stones. In fact, the National Kidney Foundation notes eight out of 10 kidney stones are oxalate stones.
• Drinking excessive quantities of water and herbal tea while not eating much, or any, food for several days can cause serious electrolyte imbalances, raising your risk for potentially dangerous irregular heart rhythms.
• Radically changing your diet to go on a detox regime can also cause serious health complications if you have diabetes or other chronic health conditions. The NCCIH urges discussing any diet change with your doctor.
• Colon cleansing procedures (like laxatives or enemas) frequently used with detox diets can also cause harm, especially if you have a history of colon surgery, kidney, heart, or gastrointestinal diseases.

The potential downside to fasting

Fasting (not eating at all for a length of time) has enjoyed renewed popularity in recent years in the form of intermittent fasting (IF) — eating only during certain periods of the day (usually 8 or 12 hours) or eating every other day and fasting the rest of the time.

Some research shows IF, especially when you eat food during an 8-hour window during the day, may have health benefits, including helping control both weight and blood sugar levels. A study by University of Alabama researchers, for example, found obese men with prediabetes who fasted using this approach lowered their risk of type 2 diabetes, reduced their high blood pressure, and lost weight.

Other studies have shown IF works no better than simply cutting calories to control weight.

The not-eating-at-all for a day type of fasting can cause people to go overboard on food when their fasting period ends. More serious potential health consequences of fasting, the NCCIH notes, include headaches, dehydration, weakness, and sometimes fainting.

That’s why anyone with an ongoing chronic health condition, including diabetes and heart disease, should talk to their doctor before opting for any form of fasting.

Who benefits from a gluten-free diet — and who doesn’t?

People with celiac disease, a digestive disorder, should strictly follow an alternative diet — specifically one that avoids gluten, a protein found in wheat, barley, and rye. Gluten damages the small intestine of people with celiac disease and can keep their bodies from absorbing needed nutrients, the National Institute of Diabetes and Digestive and Kidney Diseases explains.

But gluten-free diets have gained popularity among people without celiac disease, who claim they have lost weight, improved digestion, and generally feel better if they avoid gluten. While cutting down on gluten-containing grains can reduce calories and result in dropped pounds, there can be a downside to your health if you don’t have celiac disease.

A study from Columbia University and Harvard University researchers, published in BMJ (British Medical Journal), found limiting whole grains as part of a reduced-gluten diet may increase the risk of heart attacks.

“Popular diet books, based on anecdotal and circumstantial evidence, have pushed the notion that a low-gluten diet is healthy for everyone,” said Columbia University Medical Center gastroenterologist Benjamin Lebwohol, MD, who headed the study. “Our findings show that gluten restriction has no benefit, at least in terms of heart health, for people without celiac disease. In fact, it may cause some harm if they follow a low-gluten diet that is particularly low in whole grains because those grains appear to have a protective effect against heart disease.”

In addition, the American Heart Association notes eating gluten — if you don’t have celiac’s disease — can help lower your risk of type 2 diabetes. That’s important for heart health because diabetes increases your odds of developing heart disease.

“Gluten-free foods often have less dietary fiber and other micronutrients, making them less nutritious, and they also tend to cost more. People without celiac disease may reconsider limiting their gluten intake for chronic disease prevention, especially for diabetes,” public health researcher Geng Zong, PhD, advised.

What you need to know about low carb, no carb and carnivore diets

Eating a diet low in carbohydrates for weight loss first became a weight loss craze in the l970s, popularized by Robert Atkins, MD. Limiting the amount of carbs you eat to lose weight wasn’t a new idea. But the publicity around Atkins’ bestselling book on the subject, and people sharing how fast they could drop pounds on a low-carbohydrate, high-protein diet, made the idea enormously popular.

A low-carb diet causes weight loss because it pushes your body to use fat stores for energy. Researchers have found that keeping lowering your carb intake may help keep weight under control, lower your risk of type 2 diabetes, and help regulate blood sugar — especially if you continue to eat some fruits, vegetables, and whole grains.

But, over the decades, the Atkins Diet inspired other versions of low-carb diets that cut out many healthy foods and promote more radical weight loss, going to even lower or no-carb modes of eating. While such alternative fad diets do rev up fast weight loss, they can come with worrisome side effects and potential risks to your health.

A low-carbohydrate diet produces ketosis, which breaks down chemicals called ketones (made by your liver) that build up in your body as fat stores. Ketosis can cause headaches, muscle cramps, fatigue, constipation, diarrhea, and even bad breath.

The ketogenic diet (keto, for short) pushes the low-carb approach far lower than the original Atkins diet to keep your body in a state of ketosis. It involves relying on very low-carb meals that are typically high in fat from meat, butter, and oils.

While the keto diet may cause you to drop pounds quickly and lower your blood sugar levels, it’s hard to sustain and comes with potential side effects. Any weight you lose on the diet comes back — often with more pounds — when you go off the diet. And many people do give it up eventually because the diet is hard to maintain.

The keto diet can cause low blood pressure, constipation, deficiencies in important nutrients, and lead to kidney stones, too, according to University of Chicago dietitian Mary Condon, RN. It’s also not a safe diet for anyone with gallbladder, liver, thyroid, or pancreas health conditions, Condon points out.

Low-carb diets have also been linked to an increased risk of the heart arrhythmia known as atrial fibrillation, according to a study of more than 13,000 middle-aged men, published in the Journal of the American Heart Association. Atrial fibrillation is linked to an increased risk of blood clots and strokes.

The carnivore low-carb diet (sometimes called the zero-carb diet) relies almost totally on meat and other animal products, eliminating vegetables, grains, nuts, seeds, fruit, and any starches. You’ll lose weight, but, odds are, you are raising your risk of heart disease and certain cancers because your diet is high in fat from animal sources. You also may be shortening your life.

An analysis of studies involving more than 432,000 people in more than 20 countries found radical, low-carb fad diets may decrease lifespan. The study concluded that people who relied on low-carb diets heavy in animal proteins and fat had a greater mortality risk than people whose diets contained more fats and protein from nuts, legumes, and vegetables.

Longer lives were associated with diets that are not extremely low on carbs and not loaded with them, either. Moderate carb intake appears to be the healthiest way to eat.

"Low-carb diets that replace carbohydrates with protein or fat are gaining widespread popularity as a health and weight loss strategy. However, our data suggests that animal-based low-carbohydrate diets, which are prevalent in North America and Europe, might be associated with shorter overall life span and should be discouraged,” said Brigham and Women's Hospital cardiology researcher Sara Seidelmann, MD, PhD, who led the research.

Get facts about the health effects of alternative diets

If something sounds too good to be true — including a diet that can make you slim and trim easily — it probably is. Be aware that testimonials claiming a certain fad or alternative diet cured a health problem are not the same as studies published in reputable scientific journals. What’s more, websites selling products that promote diets are not good sources of nutrition or weight loss information.

Look for reliable sources like the CDC, the National Institutes of Health, and your healthcare provider. And never start a new diet without talking to your doctor, especially if you have a chronic health condition.

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