Diet or exercise? Which one is more important?
We all know that if we want to lose weight, we need to burn more calories than we consume. To achieve this, we need to eat less and move more.
But the problem is all of us are constrained by a finite amount of resources. We don’t have as much time, energy or money we want to spend on being healthy.
So if we could do only one, which one should we do? Which one is more important for weight loss? Diet or exercise?
This is one of the most frequent questions that’s asked by aspiring fitness enthusiasts. In this article, we decided to take a look at the evidence.
Diet or Exercise: The Secret of Weight Loss
As we mentioned above, you only lose weight when you burn more calories than you consume. You gain weight when you consume more calories than you burn.
In order to lose one pound of fat, you need to create a 3,500 calorie deficit. You can do it either through Diet or exercise.
You burn far fewer calories than you think by exercising. For example, thirty minutes of jogging might burn off 350 calories. But most of us can’t keep up a strenuous 30-minute exercise regimen every day of the week.
Let’s imagine, you are a 200-pound man. You want to lose one pound in a week without changing your diet. To achieve this, you need to run about 3.5 miles per day (or 24.5 miles total).
Now, if you want to lose one pound in a week without changing your exercise regime, you need to cut back 500 calories/day. That means eliminating two Starbucks Frappuccinos each day.
Keep in mind that all of this is in theory. Reality doesn’t always follow theory. So let’s take a look at what the research says.
What Research Says About Exercise
In one study, researchers selected 320 postmenopausal women. Their weight ranged from normal to obese. They were randomized to either an additional exercise or no additional exercise group.
Both groups were instructed not to change their diets. Those in the exercise group did moderate-vigorous aerobic exercise for 45 minutes, 5 times a week for a year.
At the end of the study, researchers found that compared to the no additional exercise group, subjects of the exercise group lost an average of 2kg (4.4 lbs) of fat.
Researchers also found that the subjects in the exercise group actually exercised for an average of 3.6 days each week instead of 5 days a week. So they exercised a total of just under 155 hours in a year.
That means they had to exercise 77 hours for each kg of fat lost.
This is not the only story that found that the weight loss benefit of exercise isn’t so impressive. This 2001 review of exercise intervention studies found that “the amount of exercise energy expenditure had no correlation with weight loss in these longer studies.”
This Cochrane Review looked at all the best-available evidence on exercise for weight loss. They found that physical activity alone led to only modest reductions.
But why is this case? Why exercise are relatively Ineffective for weight loss? As we already mentioned above, you don’t burn as much calorie as you think you burn through exercise. So, calorie expenditure through exercise is relatively small. Believe it or not, most of our calories are spent every day on just staying alive. You probably know it as “resting metabolic rate.”
A 200-pound man with 30% body fat will spend about 2,100 calories without so much as getting out of bed. Exercise will barely make a dent in his overall caloric expenditure.
Exercise also increases your appetite. Exercise also make you overestimate the number of calories you’ve burned. As a result, you reward yourself with food. This may even result in weight gain. Research confirms this.
What Works for Weight Loss
Exercise has many benefits. It can lower your risk of many diseases. It reduces the risk of including stroke, heart attack, type 2 diabetes, osteoporosis and some cancers. It reduces your blood pressure and triglycerides in the blood.
It may also reduce your risk of developing cognitive impairment from Alzheimer’s and dementia.
But it isn’t the most important thing when it comes to weight loss. Every reliable expert on weight loss says the most important thing you can do to lose weight is to limit calories.
Take a look at this randomized trial that was done on a group of overweight folks. The group that restricted calories lost about the same amount of weight as the group that dieted and exercised.
What if you didn’t choose between diet or exercise? What happens if you combine calorie cutting with exercise? It will work better than calorie cutting alone. But you will only get marginal additional weight-loss benefits.
In one study, researchers from the National Weight Control Registry parsed the habits and behaviors of adults who have lost at least 30 pounds and kept it off.
They found that all of them share a few things in common: cut their calories, stay away from high-fat foods, and exercise regularly. They use physical activity in addition to calorie counting.
If you incorporate calorie cutting with exercise, just don’t factor exercise into your caloric expenditure or intake. Pretend you didn’t exercise at all. This will help you get the best results.
And keep in mind: Weight is lost in the kitchen, health is gained in the gyms.