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Weight Loss Misconceptions

8 Myths — and 1 Truth

“Lose 10 pounds in a month!”

“5 weight-loss tricks!”

“Shed pounds fast!” 

We’re so inundated by advertisements for weight loss programs, tips and products that it’s easy to lose track of what’s real and what’s fake on the quest to lose weight

Elizabeth A. Lowden, MD, is a bariatric endocrinologist at Northwestern Medicine. She shares seven common misconceptions about weight loss. 

Myth No. 1: Once you start, you’ll keep losing weight. 

“The concept that you’ll lose weight as long as you burn more calories than you consume leads people to think that weight loss should be a linear process,” says Dr. Lowden. “So many other factors come into play.” 

Metabolic Rate

Your metabolic rate is how many calories your body burns at rest. It changes as your weight comes down and depends on a variety of factors. Some you can’t change, like your height, gender at birth and age. Others you can, like muscle mass. 

You burn more calories if you have more muscle in your body. If you’re losing weight without doing a strength-training program, your metabolic rate will eventually decrease due to decrease in muscle. You’ll start burning calories more slowly, and your weight will plateau. 

Your body also adjusts to the amount of calories you’re giving it. This concept is called adaptive thermogenesis

“Imagine your metabolism like a furnace,” says Dr. Lowden. “If you’re not feeding the furnace, the flames will go down, reducing your metabolic rate.” 

When you begin a weight loss program by changing your diet and exercising more, your initial loss will be water weight. Eventually, your weight will remain stagnant unless you make further changes by increasing activity level and decreasing calorie intake. 

Hormonal Changes 

Women who have menstrual cycles will likely see more fluctuations in their weight as well. 

“Due to hormonal changes that cause water retention, weight loss for women may look like down, down, up, down, up; it won’t be a steady loss,” says Dr. Lowden. 

Myth No. 2: Supplements can help you lose weight.

“Literally nothing that you can get on the market or through a physician will increase your metabolism,” says Dr. Lowden.

Some supplements assist in weight loss by decreasing appetite, but nothing can change your metabolism. 

“Many supplements deemed ‘fat burners’ contain caffeine, chemicals and herbs that can be very dangerous,” says Dr. Lowden. “These ingredients can have negative cardiovascular implications.” 

Myth No. 3: Obesity is not genetic.

Some people do have genetic syndromes that lead to obesity, such as Prader-Willi Syndrome.

Other people have genes that can be turned on or off depending on their environment, which can also lead to obesity.

“There are certain genes that impact how your body processes sugars, carbohydrates and fats,” says Dr. Lowden. “Some people have a greater propensity for being overweight based on lifestyle choices that can impact these genes.” 

If this is the case for you, good news: You can change this. 

“If these are the cards you’ve been dealt, it’s not the end of the world,” says Dr. Lowden. “You just have to be more conscientious about your diet and activity level.” 

Myth No. 4: You can be “healthy-fat.”

“There’s no such thing as being ‘healthy-fat’ because the extra weight could be causing health implications that we can’t measure with our current science,” says Dr. Lowden.

There’s also a misconception that thinner people are healthier. This is not always the case, as weight is only one of many measures for health. There are plenty of people within a healthy weight range that have very unhealthy habits, such as smoking and poor diets. 

Weight and body mass index (BMI), a measure of weight compared to height, are not accurate measures of health, as they don’t account for visceral fat, or the fat that surrounds your organs and can cause insulin resistance and cardiovascular complications. 

“Using BMI can give us a false idea about who has weight issues and who doesn’t,” says Dr. Lowden. “If you were to look at Lebron James’ BMI, he’d technically be in the overweight range. We know that as a professional basketball player, he’s likely healthy.” 

BMI doesn’t show the whole picture. It’s one measure. Regardless of weight or BMI, your health habits could be putting you at risk for a variety of health issues. 

Myth No. 5: Fad diets work

Fad diets don’t work because they’re typically unsustainable in the long term,” says Dr. Lowden. “Significantly reducing calories and cutting out whole food groups leads to short-term success, but sustainable weight loss comes from lifestyle change.”

Fad diets increase the chance of yo-yo dieting, which has been shown to increase morbidity.

“When you lose weight rapidly on a fad diet, you lose muscle mass. The weight comes back as fat, not muscle, which makes it harder to lose weight again.” 

Psychologically, fad diets disconnect you from your own satiety signals. 

“Our bodies have a capacity to tell us what we need, but we stop listening when we’re very young,” says Dr. Lowden.  

Myth No. 7: Your diet doesn’t matter as long as you just exercise more.

You can lose weight by burning 500 more calories than you eat.

You can burn 500 calories by walking or running five miles, or doing one hour-long high-intensity spinning class.

It’s easier to attain this 500-calorie deficit by reducing caloric intake throughout your day with small changes. Maybe you skip the cheese on your salad, or pass on a side of toast at breakfast. 

If you’re justifying overeating with exercise, you’ll have a harder time losing weight. You can’t run away from a bad diet.

Myth No. 8: You can eat as much healthy food as you want.

If you’re eating too much food, it doesn’t matter how healthy it is.

Eating a healthy, balanced diet is important, but it’s possible to overeat even the healthiest foods, like vegetables. 

“I have patients who complain about not losing weight on a clean and healthy diet,” says Dr. Lowden. “We usually determine that they’re just eating too much of a clean and healthy diet, and make portion changes accordingly.” 

Fact: One diet doesn’t fit all. 
“Losing weight and keeping it off are a lifestyle,” says Dr. Lowden. 

Finding a weight loss plan that works for you will take trial, error and knowing the truth about what’s happening in your body when you lose weight. 


Weight Management

Elizabeth A. Lowden, MD
Elizabeth A. Lowden, MD
Nearest Location:
Health System Clinician, Feinberg School of Medicine
  • Primary Specialty Bariatric Endocrinology
Accepts New Patients
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