If you’ve ever Googled, “Is diet or exercise more important for weight loss?” you’ve probably come across this seemingly arbitrary formula for dropping pounds: 

It’s 80% diet and20% exercise.

But where did this ratio come from? And what does it really mean?

At a physiological level, weight loss and weight gain revolve around caloric consumption and expenditure. Putting simple, the basics of calories: we lose weight when we eat fewer calories than we expend. Conversely, we gain weight when we eat more calories than we expend. 

So we can either eat less or expend more.

In order to lose1 pound (~0.45 kg) of fat, we must create a 3500 calorie deficit, which can be achieved through either exercise or diet or both.

Now to explain this ratio let us take an example.

Let’s say that a 90 kg man wants to lose half a kilo in one week.

Through exercise alone: He needs to run about 6 kilometers per day or 42 kilometers in a week,assuming his diet remains the same.

Through diet alone: He needs to cut back 500 calories per day (equivalent of 2 aaloo parathas), assuming his work level remains the same.

Ask anyone to choose, and the answer would be “I would rather cut 2 aaloo parathas from my diet daily than run 6 kilometers a day to lose half a kilo!!!!”

Then why exercise?Why even 20% when all the 100% can be achieved by diet?

The National weight control registry, established in 1994 by scientists at the university of Colorado and Brown Medical School, is following more than 10,000 Americans who have lost weight and kept it off for years. Just 1% kept the pounds off with exercise alone, 10% did it with diet alone and 89% used both.

Not convinced enough to exercise?

Michele Olson,PhD, Professor of physical education and exercise science at Auburn University at Montgomery, Alabama explains that with diet alone, only a portion of weight is loss from fat while muscle and bone density are lost too. 

Exercise stimulates growth of these metabolic tissues, thereby ensuring that you are burning mostly fat. The number on the scale may not sound as impressive but because muscle takes up less space than fat does, you look smaller and your clothes fit better with exercise.

Thus summarizing it up: What you eat matters more than how you work it off, but fitness will push you past plateaus and help you achieve your ultimate goals.

As rightly put by Dr. Yoni Freedoff who runs one of the largest obesity clinics in Canada and has helped countless individuals lose weight with a health and fitness approach “Sure, weight is lost in the kitchen, but health is gained in the gyms”