No, you can't just "burn off" bad food.
At least once a week, a client tells me how confused they are about nutrition—and I get it. With so much information and conflicting advice floating around, it’s easy to feel mixed up. But busting myths, and explaining the science behind healthy eating is one of my favorite parts of my job. Here are five of the most common misconceptions I hear, and why you can let them go for good.
MYTH: When you eat junk food, you can just burn it off.
It's not that simple. The quality of what you eat matters—a lot. And the damage from unhealthy food simply can't be undone with a tough workout. A 2015 study, for example, found that artificial additives from processed foods may raise a person's risk of developing autoimmune diseases.
Trying to compensate for poor diet choices with exercise is actually a double whammy: Physical activity puts stress on the body, and without adequate nutrition to recover from the wear and tear, you can become weaker rather than stronger. A balanced, whole foods diet is important for everyone. And if you’re regularly active, it’s even more important, not less.
MYTH: It's OK to eat as much protein as you want.
Most of my clients are concerned about overdoing it on carbs. But the truth is you can eat too much of any macronutrient, including protein. The protein you eat maintains, heals, and repairs tissues in the body made from this building block. But you only need so much protein to accomplish these tasks. When you exceed the amount, the surplus protein can either prevent weight loss, or cause weight gain.
To strike a good balance, include some protein in each meal, but don’t go crazy. A good rule of thumb: If you’re active, to aim for half a gram of protein per pound of your ideal weight. So if your goal is 130 pounds you need no more than 65 grams per day.
You can achieve this amount with two eggs at breakfast (12 grams), one cup of lentils at lunch (16 grams), a quarter cup of almonds as a snack (6 grams), and 6 ounces of salmon at dinner (33 grams). Timing also matters. To help your body make the most of the protein you eat, it should be spread out throughout the day.
MYTH: Eating after your exercise cancels out your workout.
Nope, the calories you consume post-exercise aren’t immediately shuttled back into your fat cells. In fact, it's important to eat after a sweat session.
Working out takes a toll on your body, and afterward your body is primed for recovery: Eating a clean, nutrient-rich meal or snack provides your cells with the raw materials needed to heal and repair. This recovery process is key, because it’s not just the training itself, but the healing from the training that builds and maintains muscle mass, boosts metabolism, and improves your fitness level.
For the best results, choose post-exercise foods that deliver vitamins, minerals, antioxidants, lean protein, and healthy fat, like a salad topped with salmon or beans and avocado; or a protein smoothie with veggies, fruit, and almond butter.
MYTH: Fruit is as bad as candy.
Some of my clients avoid fruit, fearing that natural sugar leads to added pounds. But a recent Harvard study found that shunning fruit altogether isn’t necessary for weight management. The researchers looked at more than 130,000 adults, and found that those who ate an extra daily serving of fruit shed an additional half a pound over a four-year period. While that may not sound significant, it could help offset typical age-related weight gain.
Fruit is also packed with important nutrients, water, and fiber. And its naturally occurring sugar is less concentrated than other sweet foods. For example, one cup of whole strawberries naturally contains about 7 grams of sugar, compared to about 13 grams in one tablespoon of maple syrup, 17 in a tablespoon of honey, 21 grams in 17 gummy bears, or 30 in a 12 ounce can of cola.
Some research even shows that compared to veggies, fruit may have a more powerful effect on lowering weight. This may be because fruits tend to replace higher-calorie goodies and treats, whereas veggies tend to be add-ons. Bottom line: with so many benefits, fruit is definitely worth including in your daily diet, as long as you don’t overdo it. Aim for at least two servings a day, maybe one with breakfast, and another as a snack or dessert. Reach for more if you’re especially active.
MYTH: Eating fat makes you fat.
Despite the best attempts of nutrition experts (including me) to dispel the notion that eating fat makes you fat, fat phobia still exists. Clients continue to tell me they avoid avocado, or choose low-fat salad dressing because they’re watching their waistlines.
Eating the right fats, however, is actually a smart strategy for weight loss. Healthy fats are incredibly satiating. They keep you fuller longer, and research shows that plant-based fats like olive oil, avocado, and nuts increase appetite-suppressing hormones.
Plant fats have also been shown to reduce inflammation and boost metabolism, and they can be rich sources of antioxidants. Aim to include a portion of healthy fat in every meal and snack.
Need some ideas? You could add avocado to an omelet, or whip it into a smoothie. Add nuts or nut butter to oatmeal. Drizzle garden salads and vegetables with extra virgin olive oil. Snack on veggies with guacamole or tahini as a dip. And enjoy a bit of dark chocolate as a daily treat.
Cynthia Sass is Health’s contributing nutrition editor, a New York Times best-selling author, and a consultant for the New York Yankees.