If you want to live longer and feel better, stop following food trends.
Every few months, a new “miracle” plan like the keto diet, intermittent fasting, carnivore, raw food, etc. promises to solve everything. Most are not. Even modest results are rarely worth the time, effort, and mental energy required.
As a Harvard-trained oncologist and world leader in health policy, I have spent decades researching what actually improves health outcomes. The answer to living longer is very simple. Good nutrition is about developing habits that last for years, not weeks.
Everyone’s needs are different and you should consult your doctor before making any changes to your diet, but here are six nutrition myths we wish more people would abandon.
1. All snacking is bad.
The average adult consumes nearly 500 calories per day from snacks, many of which come from ultra-processed foods like potato chips, cookies, and packaged desserts. These foods are designed to encourage overeating.
In one study, participants who ate ultra-processed foods consumed more calories and gained 2 pounds in just two weeks compared to participants who ate whole foods, even though the calories were the same. These foods are also associated with increased all-cause mortality.
Not all snacks are harmful. Research shows that healthy snacks can improve overall diet quality. Nuts, fruit, yogurt, hummus, and vegetables provide fiber, protein, and healthy fats that promote satiety without spiking blood sugar levels.
2. You need to eat more protein.
Most Americans already consume enough protein. The recommended intake is approximately 0.75 to 1.0 grams per kilogram of body weight per day (approximately 45 to 70 grams for most women and approximately 55 to 90 grams for most men).
Protein powder is also not the solution. In one analysis, two-thirds of the protein powders tested contained dangerous levels of lead. There is an exception:
Adults over 60 years of age, whose muscle mass decreases with age, may benefit from approximately 1.2 g/kg. Athletes or people recovering from illness may require up to 1.5 g/kg
For everyone else, whole food sources (beans, lentils, yogurt, fish) are safer and more beneficial than supplements or excess red meat.
3. Fiber supplements work just like whole foods
Only about 7% of American adults meet the recommended fiber intake, which is a serious problem.
A high-fiber diet is associated with a lower risk of colorectal cancer, lower incidence of type 2 diabetes, and a 31% lower risk of death from coronary heart disease.
However, fiber supplements are not a perfect shortcut. Most foods contain only one type of fiber and do not replicate the complexity and variety of fiber found in natural foods. Only a few show meaningful clinical benefit.
Fruits, vegetables, beans, and whole grains remain the most effective ways to support gut health.
4. Low-fat dairy products are always better
Dairy consumption, regardless of fat content, is associated with lower risk of type 2 diabetes and improved growth in children.
The idea that high-fat dairy products cause weight gain is not supported by evidence. In fact, research shows that children who consume full-fat dairy products are less likely to be overweight or obese than children who consume low-fat dairy products. A similar trend is seen in adults.
Fat content alone does not determine health. Full-fat dairy products can be incorporated into a balanced diet, especially when replacing ultra-processed “low-fat” alternatives.
Choose the version you enjoy and stick with.
5. All fat is bad
For decades, Americans have been told that fat makes you fat. This has been proven wrong. However, as dietary fat intake decreased, rates of obesity and diabetes soared.
Healthy fats are essential. Many calorie-dense foods, such as nuts, olive oil, full-fat dairy products, and even dark chocolate, are known to cause less weight gain than processed grains and sugary snacks.
There is strong evidence for liquid vegetable oils, especially extra virgin olive oil. Even half a tablespoon a day has been shown to reduce the risk of death by 19% over nearly 30 years.
Fat is not the enemy. It’s ultra-processed, low-fiber, high-sugar foods that cause weight gain and metabolic disease.
6. You can exercise with fewer calories
Many people believe that additional training can counteract an unhealthy diet. Unfortunately, that’s not possible. There’s more than a grain of truth to the saying, “You are what you eat.”
A recent study found that humans burn about the same amount of calories per day regardless of their activity level. Exercise improves health, but it doesn’t provide the calorie “bonus” people expect. What and how much you eat affects your weight.
However, exercise is still essential. Improves sleep, mood, cognition, bone density, and social connection. Walking, especially with others, is one of the most effective and accessible forms.
Good nutrition means designing a life that makes healthy choices that are easy and sustainable for years: whole foods like fruits, nuts, and vegetables, modest portions, and meals shared with people you love.
Skip the detox. Reserve the olive oil. And yes, eat ice cream once in a while.
Dr. Ezekiel J. Emanuel is an oncologist, vice chancellor, professor of medical ethics and health care policy at the University of Pennsylvania, and author of Eat Ice Cream: Six Simple Rules for a Long, Healthy Life. Previously, he served as Director of the Division of Bioethics at the National Institutes of Health and on the faculty of Harvard Medical School. Dr. Emanuel received his MD from Harvard Medical School.
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