With so much advice out there on the best ways to lose weight, it can be hard to separate diet fact from fiction. Unfortunately, many of the so-called "rules" of weight loss are at best ineffective — at worst, they might actually make you gain weight.
Here, doctors who specialize in weight loss explain the tactics you should ignore and the ones worth paying attention to.
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1. 'You Are What You Eat'
If you're only worrying abut what you eat, you aren't seeing the whole picture.
"Diet is only one of the components of weight management," says Marcio Griebeler, MD, director of the Obesity and Medical Weight Loss Center at the Cleveland Clinic's Endocrinology & Metabolism Institute. "It's much more than that. Don't just focus on a diet, focus on a healthy lifestyle."
Dr. Griebeler uses a holistic approach for his patients that includes nutrition but also addresses appetite control, the psychology behind eating behaviors, exercise, stress and sleep (more on that in a minute). All of these factors can contribute to weight gain and prevent weight loss.
Take stress, for example. When you're chronically stressed out, your body produces a lot of the hormone cortisol, which can rev up your hunger and negatively affect your metabolism, per a November 2015 study in Sleep Science.
That's why part of your weight-loss plan should include a goal to lower your stress levels. Journaling, dancing and deep breathing are just a few simple daily habits that can help.
2. 'You Should Skip Sleep to Work Out'
Regular exercise is important for weight loss and good health, but it's sometimes hard to fit it in. While it may be tempting to set the alarm clock an hour earlier to get your workout done, this approach could backfire.
"Sleep deprivation stops your body burning calories so efficiently and can also make you eat more," Craig Primack, MD, president of the Obesity Medicine Association and co-founder of Scottsdale Weight Loss Centers in Arizona, tells LIVESTRONG.com.
When you don't sleep well, your levels of the appetite-suppressing hormone leptin go down, while your levels of the hormone ghrelin — which makes you feel hungry — go up, Dr. Primack explains. (Hello, cravings!)
Shorting yourself on sleep (meaning: getting fewer than seven hours a night) could also undermine your exercise efforts. When you restrict calories and sleep at the same time, your body loses more lean muscle than fat, according to an October 2010 study in the Annals of Internal Medicine. And less muscle means a slower metabolism (the rate at which your body burns calories), per the Mayo Clinic.
"Is it better to wake up early and exercise or get that seventh hour of sleep?" says Dr Primack. "I think it's better to spend that hour of sleep."
With that said, exercise is essential for a healthy lifestyle. Adults should aim for at least 150 minutes of moderate cardio a week, per the Centers for Disease Control and Prevention. So, ideally, you'll want to squeeze in a half hour most days. But maybe that means going for a walk after dinner instead of watching TV, or going to bed earlier so you can get up for that morning jog.
3. 'All Calories Are Created Equal'
Losing weight isn't just about reducing calories, but eating the right type of calories.
"One of the most common misconceptions is that a calorie is just a calorie, so it doesn't matter what we eat — only how many calories we eat," Michael Greger, MD, nutrition expert and author of How Not to Diet, tells LIVESTRONG.com. "The notion that a calorie from one source is just as fattening as a calorie from any other source is a trope broadcast by the food industry as a way to absolve itself of culpability."
In other words, 100 calories from a banana is not the same as 100 calories from a brownie. For one, the banana calories come with a host of good-for-you nutrients, including fiber, which helps you feel fuller longer, and B vitamins, which support a healthy metabolism.
Plus, processed foods like packaged snacks and desserts, sugary drinks and processed meat have been linked to weight gain. A December 2017 analysis in Current Obesity Reports found that eating more processed foods ups your risk for obesity and metabolic syndrome as well as high blood pressure and cholesterol.
According to the 2020-2025 Dietary Guidelines for Americans, a healthy diet limits added sugars, saturated fat, sodium and alcoholic beverages and contains a variety of fruits, vegetables, whole grains and lean proteins.
4. 'Your Body Needs to Be Cleansed'
You don't need to do a juice cleanse or "detox" to lose weight — or to reach any health goal, for that matter. Your body is very good at processing toxins and getting rid of waste, Dr. Primack says.
What's more: While a cleanse may lead to weight loss, it's only because you've flushed all the food out of your GI tract, not because you've actually lost body fat.
"You lose weight, but you are not changing anything in your metabolism," Dr Griebeler says. And it's only temporary: "At some point you will eat again," he says, and the number on the scale will creep back up.
"Our main goal when we talk about weight management is actually to avoid being hungry. If you skip meals, you're going to be hungry, and that's not a good situation."
5. 'Skipping Meals and Snacks Cuts Calories'
Although it might seem counterintuitive, cutting out snacks and skipping meals may actually prevent weight loss. The reason? The lack of self-control you have when you are "hangry."
In other words, skipping meals and snacks increases the likelihood that you'll overeat later in the day, Dr. Griebeler says.
"Our main goal when we talk about weight management is actually to avoid being hungry," he says. "If you eat healthily, you won't be hungry. If you skip meals, you're going to be hungry, and that's not a good situation. You then don't make the right choices."
A much-cited July 2003 study in the American Journal of Epidemiology looked at the association between eating patterns and obesity and found that eating four or more times a day was inversely correlated with obesity — the more frequently participants ate, the less likely they were to have overweight. Those who skipped breakfast were more likely to have obesity.
This may be surprising if you've heard that intermittent fasting helps with weight loss, but here's the deal: If you're still eating the same amount of calories but just in a shorter time period, you aren't going to lose weight. The only way to lose weight — via intermittent fasting or otherwise — is to eat fewer calories overall.
Plan out your meals and snacks in advance. If you know what you're going to be eating, you're less likely to make a bad choice and eat too many calories.
6. ‘If You Can’t See Results, You’re Not Making Progress’
Long-term, sustainable weight loss doesn't happen overnight. So even if you don't see results in the mirror or on the scale, that doesn't mean you're not making headway.
"The number on the scale is just that, a number," says Jenny Seger, MD, an obesity medicine specialist. "Progress is not always reflected by the number."
In fact, you might even gain weight if you're strength training and building lean muscle. "That's great progress, as having more muscle mass is a way to turn up the dial on one's metabolism (i.e., how many calories you burn on any given day just living)," Dr. Seger says.
When you're evaluating your weight-loss progress, Dr. Seger recommends using other indicators than weight, such as how you feel emotionally and physically on a daily basis. Has your energy increased and your mood improved? Are you sleeping more soundly? Do your clothes fit better? These are all signs that you're moving in the right direction.
7. ‘Body Mass Index Is an Accurate Indicator of Obesity’
Calculated from your height and weight, body mass index (BMI) approximates your body fat and is often used to gauge your risk for certain health conditions, such as heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems and some cancers, according to the National Heart, Lung, and Blood Institute (NHLBI).
But it's not always an accurate estimation of obesity. For starters, it doesn't take important factors into account like body type, bone density, ethnic or racial differences and muscle mass.
For example, "if we looked only at body mass index and not body composition, many elite athletes would be considered overweight or obese," Dr. Seger says.
That's because BMI can overestimate body fat in those with a lot of lean muscle. Conversely, BMI may also underestimate the amount of body fat in older people and those who have lost muscle, per the NHLBI.
When it comes to screening for obesity and the concurrent health risks, waist circumference might be a more accurate measure. "Waist circumference is highly suggestive of increased adiposity (body fat)," Dr. Seger says.
And people with a higher proportion of abdominal fat around their waist (versus those with larger thighs and hips) have a larger likelihood of developing heart disease and type 2 diabetes, according to the NHLBI.
This risk of disease increases with a waist size that is greater than 35 inches for people assigned female at birth or 40 inches for those assigned male at birth, Dr. Seger says.
8. ‘Health Is Synonymous With the Number on the Scale’
While having overweight is associated with a higher risk for certain diseases, the number on the scale doesn't tell the whole story as far as overall health.
Indeed, a February 2016 study of 40,000 people found that more than 30 percent of "normal" weight people were cardiometabolically unhealthy, per research in the International Journal of Obesity. The same study also discovered that nearly half of people with overweight and 29 percent of those with obesity were metabolically healthy.
Instead of relying on weight as a marker of health, Dr. Seger encourages people to look at a wider array of indicators, including sleep quality, gut function, pain levels and the numbers on your blood sugar, cholesterol and liver function tests.
9. ‘Fat Makes You Fat’
"Unfortunately, dietary fat was thrown under the bus along with dietary cholesterol beginning in the 1950s, and many people, including many doctors and dietitians, still believe this to be the case," Dr. Seger says.
But there's a robust body of research that suggests healthy fats, in moderation, are essential to health and can help with weight loss. Numerous studies have demonstrated that eating a diet of reduced carbohydrates, moderate protein and healthy fats can lead to more weight loss and improvements in blood sugars, insulin, inflammatory markers and lipids versus a traditional low-fat dietary approach, Dr. Seger says.
The takeaway: Don't fear fat. Instead, incorporate heart-healthy, omega 3-rich fats like olive oil, avocado and nuts into your daily diet.
10. ‘Exercising More or Harder Guarantees Weight Loss’
In a nutshell: "Completely bogus," Dr. Seger says.
Though working out touts tremendous health benefits, contrary to popular belief, it's not a great tool for weight loss, Dr. Seger says: "I see this time and time again in my patients who come in for their initial consults completely frustrated because, despite their hard work in the gym, they aren't losing weight."
The truth is, in addition to physical activity (and diet), many factors — including age, genetics, race or ethnicity, culture, medical conditions and sleep quality — contribute to what you weigh and your ability to lose weight, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
This isn't to say you should skip the gym. Dr. Seger recommends moving as much as you can throughout the day to reap all the health-related pluses. But when it comes to weight loss, you must consider all the other factors at play.
And always focus on feeding your body nutritious foods. "The most important thing is to be intentional and mindful about what you put in your body," she says.
- USDA: "2020-2025 Dietary Guidelines for Americans"
- Nutrition: Scientific evidence of diets for weight loss: Different macronutrient composition, intermittent fasting, and popular diets
- American Journal of Epidemiology:"Association between Reduced Sleep and Weight Gain in Women"
- Obesity Review: "The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review"
- Annals of Internal Medicine: "Insufficient Sleep Undermines Dietary Efforts to Reduce Adiposity"
- Mayo Clinic: "Metabolism and weight loss: How you burn calories"
- Current Obesity Reports: "Ultra-processed Food Intake and Obesity: What Really Matters for Health – Processing or Nutrient Content?"
- Centers for Disease Control and Prevention: "How much physical activity do adults need?"
- Sleep Science: "Interactions between sleep, stress, and metabolism: From physiological to pathological conditions"
- National Heart, Lung, and Blood Institute: “Assessing Your Weight and Health Risk”
- International Journal of Obesity: “Misclassification of cardiometabolic health when using body mass index categories in NHANES 2005–2012”
- National Institute of Diabetes and Digestive and Kidney Diseases: “Factors Affecting Weight & Health”