'Clean' and Healthy Eating--What Does That Mean?

With more than 70% of Americans considered overweight or obese,^[1] and such diseases as diabetes and heart disease becoming more prevalent, some of your patients are probably looking for ways to adopt more healthful, "cleaner" eating strategies. Many of them might turn to the Internet to see which diets are trending.

Diets come and go over time. Some popular plans are nothing more than fads with little science to support them. Others have been more rigorously studied, and they do have evidence to show they work. Here's a rundown of the diets your patients might ask you about, and what the research has to say about them.

Detox and Cleanse Diets

The premise behind detox diets is to rid the body both of the environmental toxins (pollution, chemicals in foods and household products, etc) to which it is continually exposed or those that are by-products of metabolism.

Detox diets purport to accomplish this through "clean eating." That typically means eating a strict diet of fruits, vegetables, whole grains, and raw nuts and seeds, plus lots of water. Detox diets eliminate processed foods and sugar, as well as foods to which some people are sensitive, such as dairy, gluten, eggs, and red meat. Cleanse diets take the idea a step further, by limiting intake to such fluids as lemonade or green smoothies for a period of several days.

By cutting out sugary and processed foods, your patients may indeed feel better in the short-term. But there's no evidence detox and cleanse diets actually rid the body of toxins, or that they're necessary. Some of these diets, especially if they are very restrictive or incorporate fasting, can lead to nutrient deficiencies; fatigue; or gastrointestinal issues, such as nausea and cramps. The best advice you can give patients who are interested in detox and cleanse diets is to work with a dietitian to make sure they get the right balance of nutrients and calories to keep them healthy.

Paleo and High-Protein Diets

The Western diet is marked by its reliance on carbohydrates, refined sugar, and processed foods. Some experts say the excess of simple carbs in our modern diet has overloaded our body's metabolic processes, which weren't originally designed to handle so many carbs. In an effort to return to our nutritional roots, the Paleolithic, or Paleo, diet takes us back thousands of years to a time when our ancestors feasted primarily on plants and animal meat. Paleo dieters stick to protein sources, such as poultry, fish, and meat, along with vegetables and fruits. They eliminate dairy, grains, legumes, sugar, and salt.

A few preliminary studies have suggested that a high-protein diet can accelerate weight loss, and improve other health measures. A 2014 study published in the Annals of Internal Medicine found that a low-carb diet produced greater weight loss than a low-fat diet.^[2] Another report, this one in the October 2015 issue of the American Journal of Clinical Nutrition, found that the Paleo diet not only helped with weight loss, but it also improved cholesterol, triglycerides, blood pressure, and other measures of metabolic syndrome.^[3]

Because the Paleo diet limits entire food groups, patients can become deficient in such minerals as calcium and vitamin D, and they may not get their daily requirement of healthy carbs.^[4] More research is needed to confirm whether the Paleo diet offers any advantages over a well-balanced, healthy diet.

Mediterranean and MIND Diets

The Mediterranean diet, which is familiar to most of us, encompasses the tenets of healthy eating followed by people who live around the Mediterranean Sea, in such countries as France, Italy, and Spain. The diet is heavy in fruits, vegetables, fish, whole grains, and healthy unsaturated fats (olive oil), and low in processed foods, red meat, and saturated and trans fats.

Numerous studies^[5,6,7] have confirmed the health benefits of a Mediterranean style of eating, which include protection against heart disease, stroke, and dementia. Although it isn't a low-fat eating plan, the Mediterranean diet, with its emphasis on healthy fats, leads to greater long-term weight loss than a traditional low-fat diet, according to a 2016 study published in the American Journal of Medicine.^[8]

The MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet is a variation that combines Mediterranean-style eating with the DASH (Dietary Approaches to Stop Hypertension) diet used to lower blood pressure. Developed by nutritional epidemiologist Martha Clare Morris, PhD, and her team at Rush University, one study^[9] reported that the MIND diet was linearly and statistically significantly associated with lower risk of developing Alzheimer disease, lowering risk by as much as 53% in people who stick to it.

Like the Mediterranean diet, MIND focuses on fruits, vegetables, fish, poultry, and olive oil, and it limits sweets, meats, and processed foods. Where it differs is in the details. For produce, MIND adherents eat mainly green, leafy vegetables and berries, which have been shown to protect the aging brain. Although MIND wasn't designed specifically to help people lose weight, eating fewer processed and sweet foods can produce that result.

Gut Health Diet and Kombucha

Our intestines teem with a variety of microorganisms, some of which are beneficial, whereas others are potentially harmful. The gut health diet focuses on probiotics—foods that boost the population of gut bacteria thought to impede the proliferation of disease-causing microorganisms. They might also reduce gastrointestinal symptoms, such as gas and bloating, and reduce inflammation throughout the body.

Encouraging your patients to add more probiotic foods, such as cultured yogurt, kefir, kimchi, sauerkraut, miso, and tempeh, to their diet isn't likely to harm them, and it might improve their health.

Less certain are the benefits of kombucha, a popular fermented tea made with bacteria and yeast. Although it's been touted for improving everything from immune function to digestion, there's little evidence to support these claims.^[10] And there have been reports of side effects ranging from nausea to allergic reactions. In the absence of good research on kombucha tea, the best recommendation you can give your patients is to avoid it.

For Medscape, I'm Hansa Bhargava.

Follow Dr Bhargava on Twitter: @dr_hansa

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