8 reasons why most diets fail, according to a health expert

By Naveed Saleh, MD, MS, for MDLinx
Published December 5, 2019

Key Takeaways

It’s fair to say that, for many Americans, life happens between failed diets. The obesity epidemic that weighs down not just the country—but the world—reflects a lack of success to attain or maintain a healthy body weight. Diets abound, with more than 1,000 developed or approved by published experts, and still more propounded in the media.

Although most folks—physician or otherwise—have failed diets, few providers are experts on why diets fail. In an exclusive interview with MDLinx, Isabel Maples, MEd, RDN, a spokesperson for the Academy of Nutrition and Dietetics, explains the whys and wherefores of diet failure, and some tips on how to overcome them.


Diets lead to weight loss because they serve up fewer calories than most are used to, according to Maples. “The best diets have a balancing act of their own: producing weight loss quickly enough to keep us motivated while still providing enough food that feelings of starvation don’t tempt us to throw in the towel and quit.”

Pro tip: Don’t skip meals! Eat three meals a day. If needed, add one or two healthy snacks per day, so as not to feel famished.

Muscle loss

“In an ideal world, when our body weight goes down, all we lose is fat,” said Maples. “More likely, some of the weight we lose will be muscle. That’s not ideal, because muscle drives our metabolism. If we lose more muscle, we need fewer calories, and that makes weight management even harder.”

Pro tip: Refrain from cutting too many calories. Women should consume a minimum of 1,200 calories daily, and men should consume no less than 1,500 calories a day. Additionally, exercise plus a diet with 60-70 g of protein a day will also help preserve muscle. Weight training, in particular, can help stave off muscle loss. 

Physical inactivity

Intake is only half the calorie equation, with exercise being the other. Per Maples, “Our bodies are made to move! Physical activity is important for weight loss—but it’s especially important for maintaining that weight loss. Find an exercise you like and just do it. Walking is a good start. If you don’t like any kind of exercise, think of physical activity as just something you do to stay healthy, just like brushing your teeth. Whatever you do, aim for—or work up to—a minimum of 150 minutes [of exercise] a week.” 

Pro tip: Those who have been successful at losing a lot of weight and keeping it off are more likely to exercise an hour a day, according to the National Weight Control Registry.

Unrealistic expectations

“Our weight can creep up, ounce by ounce, pound by pound,” said Maples. “But when it comes to taking weight off, we want big results, fast! Think of the Tortoise and the Hare; strive to make sustainable changes. Lifestyle changes produce weight loss that is more likely to stay off.”

Pro tip: Aim to lose no more than 1-2 lb a week (or 0.5% to 1% of your body weight).

Feeling deprived

When you’re picking at carrot sticks, it seems like everybody else is ordering dessert. “We may feel deprived when we can’t indulge on holidays, special occasions and even ordinary, day-to-day eating occasions,” said Maples.

Pro tip: Switch your mindset. Instead of focusing on what you can’t have in your diet, think of your choices as active choices that you are making to be healthier. Tell yourself you can have that food if you want it, but that you only want to choose it when it brings you the most satisfaction. 

Getting discouraged

Nothing that’s truly worthwhile is ever easily obtained, and weight loss is no different. “When we lose weight, it’s not at a steady pace,” said Maples. “Slow-downs and speed bumps along the way make us feel very discouraged that we aren’t getting the results we want, especially when we are trying so hard.”

Pro tip: Track behaviors and outcomes that you can control. The scale says what it says, but only you control your actions. Remember that the scale is not your only measure of success. Instead, track other behaviors, including portion sizes, calories, choices of low-calorie vegetables, as well as gym time and pep talks.

Getting sidetracked

“Sometimes the best-laid plans can go astray,” noted Maples. “Our environment is filled with triggers, like the sight and smell of food, which can lead us off the right road. Just because you ate what you don’t think you should have, doesn’t mean you totally blew it. Focus on making progress, not being perfect.” 

Pro tip: In the long run, the worst part of feeling like you got off-track is your mindset. It may be a good idea to figure out where you were “led astray,” and brainstorm how you could handle that situation more successfully next time. And despair not; get back in the saddle again to keep making progress.

All or nothing mentality

The worst part of a diet might be the mentality that we are either “on a diet” or “off a diet.”

Pro tip: Your body is counting all the calories, even if you’re not. Healthier habits that can be incorporated into how you already eat will further help to keep the weight off in the long run.

Maples warned that when most people hear the word “diet,” they picture a new way of eating—one that places restrictions on choice and quantity. “After all, diets are designed to generate weight loss by changing the balance between the calories we take in, from food and drink, and calories we burn off, through exercise and physical activity. In other words, ‘diet’ becomes a four-letter word because it takes us out of our comfort zone and makes us do something different,” she reflected.

Need help getting or staying on track?

Find a registered dietitian in your area by visiting www.eatright.org and clicking on “Find an Expert.”

Share with emailShare to FacebookShare to LinkedInShare to Twitter