The reasoning behind the myth: Once they’re digested, carbs turn into glucose (sugar that the body uses for energy), which leads many people to believe that they should avoid carbs entirely on weight-loss diets.
The truth: According to Dr. Kahan, this is a myth in most cases. Many studies have compared low-carbohydrate diets with high-carbohydrate diets, low-fat diets, Mediterranean diets, and many other dietary patterns.
On average, there is no difference in the amount of weight that people lose between different diet types.
It’s not necessary to avoid carbs to lose weight. Some people may find it easier to lose weight when they minimize their carbohydrate intake and that’s okay if it works for them. But it’s not a requirement. It’s important to pay attention to your body and what feels right for you.
The reasoning behind the myth: The terms “low-fat” and “fat-free” are frequently used to advertise foods that can supposedly help you lose weight. But are they healthy?
The truth: This is another myth. Fat is not the enemy. There are many low-fat foods that are very healthy, but there are also many low-fat foods that are not healthy at all. For example, lots of snack foods are processed to take out the fat, but a lot of sugar is put in after the fat is taken out. Those highly processed foods are generally not very healthy and should be avoided.
The reasoning behind the myth: Since we usually go to bed — and spend less energy — fairly soon after dinner, many people believe that eating meals late at night will make you gain weight.
The truth: This is also a myth. Studies looking at the time when people eat show that in general, eating late doesn’t impact weight.
“For most people, not eating too late at night is a good strategy. Because when you are going to sleep, you don’t need too much energy for sleeping. Instead, I would rather have the energy that you can get from food during the day in order to fuel my day,” says Dr. Kahan.
However, there is no consistent scientific evidence saying that eating late is bad for you. And certainly, there is no magic hour that dictates when you can eat.
The reasoning behind the myth: Fasting has recently gained popularity as a weight management method. Some people believe that when you spend long stretches of time without sustenance, you’ll be able to lose more weight.
The truth: Fasting has been used for many centuries for different reasons, and it’s a popular recommendation for weight loss right now.
Although sometimes it can be helpful, Dr. Kahan doesn’t recommend fasting to lose weight. “Partly because it’s unsustainable. When you do some type of weight loss plan and can’t realistically continue it over time, then it’s likely — even if you lose weight — that weight will come back,” he says.
There are many studies looking at fasting in the real world. For example, during Ramadan, when people fast all day long for weeks, they don’t seem to lose weight.
“It’s almost a myth that fasting is an effective and healthy way to lose weight. Although it can be used sometimes in productive ways, most people won’t achieve any weight loss,” Dr. Kahan notes.
The reasoning behind the myth: Many people believe that in addition to keeping you full, eating smaller meals more frequently throughout the day can improve your metabolism.
The truth: This statement depends on the person. For some people, eating multiple small meals throughout the day can help them avoid getting really hungry and overeating. However, for other people, it’s not helpful. Eating more, they end up with higher blood sugar.
Some people eat only two or three meals per day rather than multiple small meals. Both are fine, and the best strategy depends on what is a good fit for you.
“This myth isn’t entirely a myth. For some people, it’s useful; for others, it’s not. It’s not a hard truth for everyone,” says Dr. Kahan.
The reasoning behind the myth: Egg yolks are a high-fat food rich in cholesterol. For a long time, it was widely believed that this dietary cholesterol could raise the cholesterol in your blood.
The truth: For most people, the cholesterol that we eat, whether from egg yolks or other foods, has little effect on the cholesterol levels in the body.
Eggs are a good example of healthy food, according to Dr. Kahan. And for most people, eggs can be part of a healthy diet and will not raise cholesterol levels.
However, there are people who are very sensitive to dietary cholesterol; their blood cholesterol levels will go up when they include cholesterol in their diet.
Dr. Kahan says that for these people, it’s important to limit foods with high amounts of dietary cholesterol, including egg yolks. But that only applies to a small number of people. For most of us, there is little or no risk of increased cholesterol from eating egg yolks.
The reasoning behind the myth: High-fat foods are also high-calorie foods. For that reason, many people avoid all kinds of fats — even healthy ones — during a weight-loss diet. This goes along with the myth that to lose weight, you need to eat less food.
The truth: In each gram of fat there are nine calories, compared with only four calories in each gram of protein or carbohydrate. For this reason, it is usually helpful to moderate the amount of fat that we eat.
However, fat is also more filling than other nutrients. When people eat some fat, they often stop eating a little bit sooner, which helps to moderate the total amount of food that they eat.
“For people who enjoy having some more fat in their diet and as part of the overall healthy dietary intake, it is perfectly okay to have a moderate amount of fat and high-fat foods in the diet as long as they do it as part of a reasonable overall healthy diet,” says Dr. Kahan.
The reasoning behind the myth: Several studies have stated that red meat raises the risk for several diseases, including certain types of cancer. However, these studies tend to include both lean and processed meats in the same category. In reality, different types of meat have different nutritional characteristics.
The truth: Consumption of red meat has some health risks. There is more saturated fat in red meat and more calories. Therefore, it’s important to moderate the amount of red meat that we eat, advises Dr. Kahan.
“However, I don’t believe that you have to avoid red meat entirely. It’s important to moderate it in our diets, but we don’t have to avoid it completely,” he explains.
The reasoning behind the myth: Instead of focusing on eating an adequate amount of food and replacing unhealthy eating habits with healthy ones, many people believe that they need to drastically reduce their food intake if they want to manage their weight.
The truth: Unfortunately, many people think moderating the amount of food that they eat means they should undereat, which is not at all healthy, Dr. Kahan explains.
For most people, decreasing food intake a little bit can be helpful for weight management. In many cases, simply by substituting some of the foods that you eat for healthier options (which often contain fewer calories), you can eat the same amount and still lose weight.
Therefore, Dr. Kahan says that it’s important to pay attention to the foods that we eat, but drastically reducing the amount we eat is neither sustainable nor healthy and should be avoided.
The reasoning behind the myth: Because many healthy diets include ingredients that tend to be expensive, many people believe it’s too costly to eat healthily.
The truth: Unfortunately, there is a lot of truth to this, according to Dr. Kahan. Often, unhealthy and high-calorie foods tend to be cheaper than healthier foods.
“It’s not impossible to eat a healthy diet that is also inexpensive, but it’s challenging due to the way our food system is set up. It takes more knowledge, time, and effort to manage your budget while also managing healthy eating,” Dr. Kahan explains.
Nevertheless, some options are choosing seasonal local foods and experimenting with recipes.
The reasoning behind the myth: It’s commonly believed that if you’re lean, that automatically means you’re healthy.
The truth: That’s absolutely a myth, says Dr. Kahan. “Some thin people are healthy. They exercise, they eat well, they work very hard. And as a result, they are able to keep fit,” he explains.
However, many thin people are not healthy. Some of them practice unhealthy lifestyle habits to maintain thinness.
Furthermore, there are many people who are thin because of their genetics, but they don’t exercise or eat healthily, and they may have other unhealthy lifestyle patterns.
Therefore, despite being thin, some people are not healthy at all.
The reasoning behind the myth: Animal products are the most commonly consumed sources of protein. Red meat, poultry, fish, eggs, and dairy are all excellent sources of protein, which is why some people believe that vegans or vegetarians can’t get enough protein in their diets.
The truth: That’s a myth, according to Dr. Kahan. You can certainly consume enough protein as a vegetarian or vegan. There are many healthy vegetarian sources of protein, such as soy, nuts, beans, and eggs.
It can be more challenging to consume enough protein as a vegetarian or vegan because your diet is more limited, but it’s certainly a myth that it’s impossible.
The reasoning behind the myth: Almost everyone has heard the recommendation to drink six to eight glasses of water per day. The idea is that water helps to flush toxins out of your body. But is two liters really the magic number that will help us stay hydrated and healthy?
The truth: Water is healthy, and it’s very valuable for managing weight and maintaining a lot of energy. But there is nothing scientific about the number of liters, says Dr. Kahan. Drinking when you feel thirsty should generally be enough to keep you hydrated.