Busting Weight Loss Myths

We know that carrying excess weight increases risk of type 2 diabetes, heart attack, stroke, certain cancers, back and joint pain, and more. Anyone who has tried knows that reaching or maintaining a healthy weight can be difficult. In today’s instant-access media culture, information, advice, and products promising to melt away unwanted fat abound. Sifting through all the misinformation and trying to separate fact from fiction can be frustrating. Here is the truth about some common weight loss myths and misconceptions:

MYTH #1: To lose weight, I have to cut out all carbs (or all fat). Cutting out an entire category of nutrients is never a good idea from a health standpoint. Our bodies require a diversity of nutrients to function. But—call it Atkins, Paleo, or keto—low-carb eating is the current rage. “Most modern carb-rich foods are ultraprocessed and high in refined starches or sugars: white bread, white rice, breakfast cereals, refined crackers, potato and corn chips, fries, bakery desserts, sweets, soda, and so on,” says Dariush Mozaffarian, MD, DrPH, dean of the Friedman School and editor-in-chief of Tufts Health & Nutrition Letter. “A ‘low-carb’ focus can help people avoid such products.”

But many other carbohydrate-containing foods—like fruits, vegetables, minimally processed whole grains, beans, and legumes—are important for health. They provide dietary fiber and phytochemicals, which have many positive metabolic effects and also are crucial to maintaining a healthy gut microbiome.

Avoiding fats may seem like a good option for weight loss because fats have more than twice the calories per gram compared with carbs and protein, but research shows this is not a good strategy. “Many trials have shown that higher fat diets, including Mediterranean-style diets and low-carb diets, are better than low-fat diets for weight loss,” says Mozaffarian. “And avoiding fat cuts out healthy unsaturated fats, like those found in nuts, seeds, fish, avocados, and plant oils.”

Myth-busting advice: Focus on eating a Mediterranean-style diet that includes minimally processed fruits, vegetables, nuts, whole grains, beans, legumes, and plant oils rich in phytochemicals; moderate fish and dairy; occasional unprocessed meat; and low intakes of highly processed foods including refined starches, sugars, and salt.

MYTH #2: While I’m losing weight, I will be hungry. Some of the best weight-loss foods are actually the most filling! Research suggests that minimally processed foods that are also high in dietary fiber (such as fruits, vegetables, nuts, beans, and whole grains) are the most satisfying. This is possibly because they are digested more slowly and the slower release of starch and sugars into the bloodstream helps us to feel satisfied longer. “Randomized trials by Susan Roberts, PhD, from Tufts show that low-glycemic, high-fiber diets both help people lose weight and reduce hunger,” says Mozaffarian. “And, a recent trial by Kevin Hall at the National Institutes of Health found that people are hungrier, eat more, and gain weight when eating ultraprocessed foods; and they feel more full, eat less, and lose weight when eating minimally processed foods.” Higher-fat, low starch, low-sugar diets also seem to help with satiety.

Myth-busting advice: Fill your plate with minimally processed fruits, vegetables, nuts, beans, and whole grains, which are high in dietary fiber, and foods rich in healthy fats to help with both weight control and hunger.

MYTH #3: Weight loss equals fat loss. Losing weight without staying active can lead to loss of muscle along with fat. Preserving (and even increasing) muscle mass is important for long-term health and for maintaining weight loss. Muscle has a positive impact on metabolism, the rate at which the body burns calories. Less muscle means fewer calories burned in a day.

Being active is important, but nearly all studies show that physical activity alone does not result in long-term weight loss. According to a 2018 review of studies published in the journal Progress in Cardiovascular Diseases, activity alone—resistance training, aerobic exercise, or a combination of both—resulted in zero to three percent weight loss, while weight-loss diets in combination with aerobic activity (like brisk walking, swimming, or bicycling) resulted in five to fifteen percent weight loss. While activity burns calories, it may increase hunger. Changing your diet is the most powerful way to lose weight, and adding exercise is even better.

Myth-busting advice: To avoid losing muscle, eat a healthy diet (like a Mediterranean-style pattern) while increasing your activity. If possible, include modest strength training exercises. Choose activities you enjoy and that fit with your schedule, making physical activity a welcome part of your lifestyle.

MYTH #4: Consuming six small meals a day, or fasting for a part of the day, is better than three traditional meals. The concept that eating smaller, more frequent meals throughout the day will help people eat less is not proven. For some people, eating every two to three hours may prevent blood sugar drops and the overeating that can result from increased hunger between meals. But other people may end up eating more if they eat multiple small meals. Similarly, while intermittent fasting may work well for some people, it may not help others. While more research is needed, studies to-date suggest that all these choices are reasonable and safe. Until more evidence arrives, the effect of meal frequency appears highly individual—see what works best for you.

Myth-busting advice: The best meal frequency plan is the one that suits your lifestyle, makes you feel satisfied and energized, and helps you achieve and maintain a healthy weight.