You’ve probably heard your diet impacts weight loss more than your fitness routine. See: “80 percent diet, 20 percent exercise” or “abs are made in the kitchen.” Yet, without much elaboration, it can be hard to tell if these sayings are simply catchy or hold any truth. So, we talked with three professionals to see if what you eat truly impacts weight loss more than exercise—and if so, by how much?
It’s all about calories in versus calories out.
In order to set this straight, we need to take a quick look at what needs to happen for our bodies to lose weight. “In order to lose weight, an energy [aka calorie] deficit needs to be created,” says Maya Feller, MS, RD, CDN, and CLC of Maya Feller Nutrition. “This deficit can come from reducing calories, increasing exercise, or both.”
If the bottom line is simply a caloric deficit, for most, cleaning up a diet is much easier than attempting to burn off all the necessary calories with exercise alone. Carrie Dennett, MPH, RDN, and owner of Nutrition by Carrie adds to that. “One possibility [why diet has more impact than exercise] is that most people don’t burn as many calories as we think through exercise, so it’s easy to ‘out eat’ your exercise,” she says. “This can happen mindlessly, or simply by falling into the mental trap of ‘I’ve been working out consistently, so I deserve this scone.’” That’s not to say that you shouldn’t treat yourself—only that those treats shouldn’t consistently out-do your workout efforts.
“You can’t outrun an unhealthy diet,” says Samantha Hass, Registered Dietitian at New York City’s F-Factor. “People tend to overestimate calories burned in the gym and underestimate their caloric intake, which negates any calories burned.” You should never use exercise as a reason to not take care of your health, or see fitness as a penance for certain food choices you regret. Accurately measure your caloric input and output if weight loss is your goal. Decouple your food intake and exercise altogether. Doing so will guarantee that key deficit.
Food quality is more important than quantity.
It’s easy to get stuck in the eat less, lose more mindset. But the quality of the food actually matters more than the quantity. “Recent studies have suggested that diet quality over quantity produces better weight loss outcomes,” says Feller. “In my clinical experience working with patients in the areas of weight management, I have seen the best outcomes with regard to sustained weight loss achieved when the emphasis is on modifying food-related behaviors and focusing on adhering to a nutrition pattern based on consuming well balanced, whole, and minimally processed foods while incorporating regular physical activity.”
Basically, whole, unprocessed foods will not only make you feel really good but help you lose weight, too. A positive relationship with food with also prevents you from spiraling into a crash diet. “We also know that engaging in positive nutrition-related behavior can be an indicator of improved quality of life as we age,” says Feller. “The phrase, ‘you are what you eat’ holds a significant amount of truth.”
Don’t stop exercising, though!
All that said, a good diet can’t provide the essential health benefits of physical activity. “Research shows that cardiorespiratory fitness is associated with better health at all body weights,” Dennett says. “And maintaining or building muscle with resistance or strength training is also vitally important for health.”
Plus, we know the benefits of working out extend far beyond weight loss. “Working out is important, as there are a number of benefits, such as aiding blood pressure and blood sugar control, improved mood, and energy balance,” Feller says.
Hass also recommends doing cardio consistently for its mood-boosting power and ability to improve heart health. Moreover, she advises those who want to lose weight to strength train. “[These] exercises create a lean physique and build lean muscle, which will boost metabolism and keep it going while not increasing your appetite like cardio does,” she says. It’s good to note that, at rest, a pound of muscle burns more calories than a pound of fat. “When you do strength training and weight resistant activities that build lean muscle, you continue burning calories, even when you stop the activity,” Hass notes.
Diet and exercise are important, but not equal.
Everything considered, both healthy diet and consistent exercise play key roles in weight loss. But your diet does outweigh your fitness routine. That doesn’t mean you should cut your workouts short! “Exercise to be strong and fit and flexible,” says Dennett. “And eat to nourish and satisfy your body and feel energized.”
Overall, the key to living a healthy lifestyle is balance. So, work to find the appropriate caloric deficit for your weight loss goals. Then, divide the work to maintain it between both your diet and your exercise.