Is Diet More Important Than Exercise for Weight Loss?

Rose Hoonan Fact Checked
© Mosuno / Stocksy United

Exercise is often thought of as one of the most important factors in any weight loss plan. But is that really the case? 

It turns out that what you eat has a greater impact on your weight loss goals than how much you exercise. Why is this the case? And what is a healthy and sustainable way to lose weight?

Vanessa Imus, a registered dietitian at the Center for Weight Loss and Metabolic Surgery at UW Medical Center - Roosevelt, explains why diet is such a key factor in weight loss and shares nutrition strategies you can take on to reach your health goals. 

Diet vs. exercise

The key to weight loss is consuming fewer calories than your body burns. You technically can reach that calorie deficit through exercise alone, but it is much more difficult to achieve — and maintain.

“It’s a lot easier to not eat the 500-calorie slice of cake than to burn 500 calories,” says Imus. “It takes a couple seconds to not have the cake, but it may take 45 minutes or more to exercise off that 500 calorie cake.”

In other words, exercising to lose weight without healthy eating is like swimming upstream. It’s much more efficient and effective to lose weight by cutting the number of calories consumed instead of increasing the number of calories burned while exercising.

“It is technically possible to out-exercise an unhealthy diet, strictly in terms of weight loss, as long as the number of calories out is higher than the number of calories you’re taking in. However, you’re still going to feel bad as long as you’re eating an unhealthy diet,” says Imus.

Instead, prioritize healthy eating — and all the benefits that go along with it — to help you reach your weight loss goals.

Creating a calorie deficit

OK, so the verdict is in: It’s easier to lose weight through diet than exercise. But just how do you go about cutting the right number of calories so that you’re not hangry 24/7, but also seeing results?

Imus has a formula for that.

“We use the Mifflin-St Jeor equation, a plug and chug formula to figure out your calorie needs,” she says. “It’s supposed to be accurate for 80% of the public. If we start someone at that calorie goal, we find that around 80% of the people are losing weight.”

While studies have shown this formula to be the most reliable in predicting the right calorie goals for each individual, Imus notes that it doesn’t work for everyone, as an individual’s metabolism might be faster or slower than the formula predicts.

“If this is the case, we figure out how many calories you’re averaging per day and subtract 500 calories from this number to come up with your daily calorie goal,” says Imus. “A 500-calorie deficit a day is equal to one pound per week of weight loss. One to two pounds a week of weight loss is usually sustainable. We generally wouldn’t recommend women to reduce calories below 1200 and men below 1500.”

To make sure you are cutting the right number of calories, and losing weight in a healthy and sustainable way, work with a nutritionist.

Healthy not hangry

As you begin any weight loss plan, it’s normal to want to see results — fast. But if you lose weight too rapidly, it can actually be unhealthy, hinder your weight loss results and make it difficult to keep off the pounds you lost in the long run. 

“If you over-restrict calories, you might be dramatically losing weight, but you’ll be constantly battling hunger,” says Imus. “And if you lose a lot of weight rapidly, you’ll hit a plateau that will be difficult to overcome since you can’t continue to reduce calories to less than your body’s basic needs.”

That plateau in weight loss happens when your metabolism slows. If you cut so many calories to start, you won’t have room to gradually cut more calories down the road. 

“By not cutting calories so drastically to start, we’ve got room to cut calories incrementally,” says Imus. “That also keeps your metabolism running more efficiently.”

As you cut calories, make sure you’re fueling your body with the nutrients you need with healthy meals (needless to say, 500 calories of cake will not provide you with the same nutrients as 500 calories of vegetables, lean protein and whole grains).

How exercise can help  

While it is entirely possible to lose weight with diet alone, incorporating exercise into your weight loss plan has benefits beyond burning calories.

“I find that exercise is so helpful for people to maintain a healthy diet, because if they’re stressed, they’ll turn to food,” says Imus. “Exercise is a great way to de-stress.”

By turning to exercise instead of food when you’re stressed, you can boost your well-being and maintain your weight loss goals. A win-win scenario.

Another thing exercise can replace? Boredom.

“If you’re bored, some people will fill that time by eating,” says Imus. “If you instead turn to exercise, it gives you something to fill that time.”

So instead of grabbing that bag of chips when you’re bored, grab your shoes and head out for a walk

The bottom line

Diet and exercise both play a role in weight loss, but it’s easier to create the calorie deficit needed to lose weight with what you consume. 

If you’re on a mission to lose weight, prioritize what’s on your plate and think of exercise as a tool to support your health goals.