The 9 Biggest Diet Mistakes People Make When Trying to Lose Weight

If you’re trying to lose weight, don’t focus solely on what you shouldn’t eat.

When it comes to dieting to lose weight, lots of people think strictly in terms of foods they need to subtract entirely from their eating regimen, says Amy Kimberlain, a registered dietitian based in Miami and spokesperson for the Academy of Nutrition and Dietetics. “People think they need to give up dairy, gluten, sugar or whatever else. Instead of focusing on what not to eat, begin to flip the thought and think about what you should add,” she says. “That might be a new whole grain, a seasonal fruit and/or vegetable or even a new nut butter.”

It’s important to keep in mind that even if you’re trying to lose weight, healthy eating isn’t strictly about restriction, but about “aiming to have a variety of foods in your eating pattern — all the colors — and ultimately feeling nourished.”

When it comes to dieting, look to reliable sources.

When it comes to dieting and losing weight, some assertions available online aren’t the most reliable. “Many people claim they are experts because they’ve researched something or because they had an experience with a health condition, and they now feel the need to recommend their choices to everyone else,” says Lise Gloede, a registered dietitian based in Arlington, Virginia. “Beware of blogs, testimonials and videos that purport to have found the ‘latest and greatest’ nutrition tips that ‘you can’t find anywhere else’ or are trying to sell you a product.”

Rather than scrolling online for information from sources of unknown reliability for information about nutrition and healthy eating, rely on institutions like the Cleveland Clinic, the American Heart Association and the Harvard School of Public Health, Gloede advises. Consulting with a registered dietitian is a good option too. Registered dietitians not only have extensive training regarding nutrition, they keep up with the latest peer-reviewed research on food and how it affects your health.

Here are nine of the biggest nutrition mistakes people make when trying to lose weight:

1. Avoiding all types of fat

For many years, fat was labeled the villain when it came to trying to lose weight. While it’s true that too much of the wrong kinds of fats can contribute to obesity and heart disease as research suggests, some fats contribute to good health, says Diane Javelli, clinical dietitian at the University of Washington Medical Center in Seattle. She’s also the owner of Belly by Javelli Digestive Nutrition, a private practice for nutrition assessment and counseling.

For example, research suggests that omega-3 fats can help reduce inflammation and lower cholesterol levels. These fats also help the body build nerve tissue and brain tissue. “Fat also helps us feel full, so may actually help with weight loss by decreasing overall portion size,” Javelli says.

Omega-3 fats are found in an array of foods, including:

— Chia seeds.

— Eggs fortified with omega-3 fats.

— Flax seeds.

Pumpkin seeds.

Seafood (salmon, shellfish and tuna).


2. Banning all carbs from your diet

It’s true that eating too many foods high in refined carbohydrates — such as white bread, white noodles, white rice and bagels and cereals made with white flour — can contribute to weight gain.

If you hear about a popular diet that requires you to eliminate an entire food group — carbs, for example — that’s a good sign that it’s too restrictive, Kimberlain says. While such an eating regimen may appear to work in the beginning, “over time it can lead to not only boredom but also lead to a lack of motivation,” she says. “Not to mention that when restricting a whole food group, you might be at risk for developing certain nutrient deficiencies.”

It’s good to keep in mind that consuming too many simple carbs can lead to weight gain and put you at risk for diabetes. Simple carbs include raw sugar, brown sugar, high-fructose corn syrup, fruit juice concentrate and glucose, fructose and sucrose.

Complex carbohydrates, on the other hand, provide many important nutrients, and include:

— Beans.


— Legumes.


— Whole grains.

So the quality of the carbs is important. “I like to think about aiming for higher-quality carbs and seeing where you might switch one out. So if you were eating instant oats in the morning, white pasta at lunch and corn tortillas at night, out of those options the instant oats and corn tortillas are whole grain (and therefore a better option).” While whole grains contain carbs, they’re a healthier option than foods made with white flour.

It’s important to note: Any food consumed in excess can lead to weight gain, not just carbs, Kimberlain adds.

3. Categorizing foods as ‘good’ or ‘bad’

Categorizing foods as “good” or “bad” can stigmatize certain foods and lead you to eliminate them from your diet, says Nicole Hopsecger, a registered dietitian with Cleveland Clinic’s Center for Human Nutrition. “Elimination of any kind can create an unsustainable diet pattern, and even affect the way you celebrate or socialize, which can be isolating. You do not need to eliminate your favorite foods in order to lose weight. Instead, try making lifestyle changes and keep them consistent.”

For example, indulge in your favorite dessert at your loved one’s birthday, but aim to have a full day of well-rounded meals before and after the party. “Remember, moderation is the key.”

4. Making poor eating choices after exercising

Who hasn’t at one point reached for a cupcake, cookies or another high-calorie treat, thinking, “I earned it at the gym” after a workout?

That may sound good in theory, but people sometimes overestimate how much they’ve exercised and how many calories they’ve burned, Kimberlain says. “So many times, you might have someone replenishing (with food) after their workout more than necessary. Not to mention that sometimes we use exercise trackers that might not be as accurate as we think in estimating how many calories we’ve burned.”

Rather than relying strictly on exercise apps or calorie trackers, Kimberlain recommends paying attention to the time and intensity of the workout. “As for nourishment, maybe something small to tide you over” until your next meal.

5. Not knowing or forgetting the basics of weight loss

Some people aren’t sure how to start when they’re embarking on a new eating regimen in an effort to lose weight. Sticking with the basics is helpful, Hopsecger says.

Here are some of the basics:

— Be mindful of portion control. (For instance, the standard serving of chicken is the size of a deck of cards. Servings of potatoes, rice and pasta should be the size of a computer mouse).

Limit added sugars, sodium and saturated fats. Read nutrition labels to find foods which are lower in these items.

— Include more fruits, vegetables and whole grains in your diet.

— Reduce (don’t eliminate) processed foods and fast foods.

The Dietary Guidelines for Americans 2020-2025 can be a useful resource for creating a healthy and sustainable eating strategy.

6. Indulging in regular cheat meals

A cheat meal is defined as one that includes foods not usually included in your diet, says Betsy Fears, a registered dietitian nutritionist who practices at RET Physical Therapy Group in Lake Stevens, Washington, about 40 miles north of Seattle. “Having cheat meals may seem like a good idea, so you can still enjoy your favorite foods, such as chips and ice cream,” she says. “But a cheat meal can turn into a cheat day, which can turn into a cheat week.”

Having the idea of “cheating” can cause some people to focus on the foods they want and to look forward to eating those items. “If you feel like you need to cheat on your diet, it’s most likely not the best eating pattern for you. All diets work because they reduce calories and create a calorie deficit. Choose one that you can realistically see yourself adopting for a long time.”

Consulting with a registered dietitian can be helpful.

7. Giving up on your diet too soon

Don’t give up on your diet just because you’re not seeing changes right away. “When people make big lifestyle changes and the scale doesn’t move after one to three weeks, they get very frustrated,” Fears says.

“Give your new regimen at least four to six weeks to work. The first few weeks are often trial and error with a lot of room for improvement. If you think you’re doing everything perfectly, then take a fine toothcomb through your new regimen — write down all the food you consume in a journal for at least two weeks, track sleep, track steps and activity minutes and record your alcohol consumption. If you’re consistent during the week but not the weekend, then work on balanced nutrition for the weekend. Consistency is the key.”

8. Setting unrealistic weight-loss goals

Success isn’t always measured strictly by the number on the scale, Hopsecger says. “Increasing fiber or reducing sugar are goals that can be measured just as well as weight changes,” she says. “Keep in mind, with increases in exercise and improvement in diet, you may be losing fat tissue and gaining muscle mass. This change in body composition is not reflected on the scale. Make diet and lifestyle changes your priority and weight loss will follow.”

Keep in mind that the Centers for Disease Control and Prevention categorizes healthy weight loss as one to two pounds a week.

“Having high expectations for quick weight loss can cause a decrease in motivation for one to continue with lifestyle changes,” she says.

9. Skipping meals

Skipping meals to reduce caloric intake for the day may actually have the opposite effect. People who skip meals may experience uncontrolled appetite leading to episodes of binge eating or overeating, Hopsecger says. “If you are excessively hungry, you’re less likely to make the right food choices that support your goals,” she says.

People who skip meals may feel sluggish or tired, which can affect their ability to exercise appropriately, which in turn can also be detrimental to their efforts to lose weight.

To recap, here are nine common nutrition mistakes people make when trying to lose weight:

— Avoiding all types of fat.

— Banning all carbs from your diet.

— Categorizing foods as “good” or “bad.”

— Eating too much after exercising.

— Not knowing or forgetting the basics of weight loss.

— Indulging in regular cheat meals or days.

— Giving up on your diet too soon.

— Setting unrealistic weight-loss goals.

— Skipping meals.

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The 9 Biggest Diet Mistakes People Make When Trying to Lose Weight originally appeared on

Update 05/24/22: This story was previously published at an earlier date and has been updated with new information.

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