When it comes to weight loss, the general rule of thumb that has proliferated the diet community has always been that it is 80% diet and 20% exercise. But is that really true? How do they come up with those numbers? I feel like it is something that is just estimated, and rather than taking those percentages as gospel, it’s more just a general way of saying that diet is much more important than exercise.
But again – is that true? Does the old adage of “abs are made in the kitchen” hold up, or is it actually more important to be getting physical activity when it comes to getting healthier and losing weight?
Diet vs. Exercise
A new study conducted by a team of researchers at the University of Colorado Anschutz Health and Wellness Center (AHWC) set out to answer the question of why so many people are struggling to keep weight off over the long-term. The study (published in Obesity journal here) consisted of comparing weight loss maintainers (those who lost weight and were able to keep it off over time) against two control groups.

The control groups consisted of a) individuals with normal body weight (a BMI comparable to the weight loss maintainer group) and b) individuals who were overweight or obese (a BMI comparable to the pre-weight loss weight of the maintainers).
The researchers studied the energy expenditure and caloric intake of the test subjects by collecting urine samples over the course of one or two weeks. They also measured their resting metabolic rate to track how much of their energy expenditure came from resting versus what came from physical activity.
What Did the Study Say?
At the conclusion of the observation period, it was found that those who were able to maintain their weight loss (defined as a reduction of body weight of 30 pounds or more for over a year) did so through reliance on physical activity, as opposed to relying on a calorie-restricted diet.
Key findings include:
As quoted by Victoria A. Catenacci, M.D., a weight management physician at CU Anschutz:
“Our findings suggest that this group of successful weight-loss maintainers are consuming a similar number of calories per day as individuals with overweight and obesity but appear to avoid weight regain by compensating for this with high levels of physical activity.”
My Takeaways
I think this is pretty eye-opening data that can have a practical use for anyone who is looking to lose weight.
Yes, it is important to watch what you eat when you are looking to shed extra pounds, but you cannot overlook the importance of exercise (especially following it consistently, like with this program).

As mentioned above, those who have maintained their weight loss are not eating any less than the individuals who are overweight. Yet, because of exercise, they are able to keep their body at a healthy weight.
One thing I would like to see more data on is what the respective diets looked like for each of the three groups studied. We know that they kept track of their caloric intake. However, there isn’t any information on how healthy those calories were. Was one group eating more nutrient-rich food than others? That can play a huge part in weight loss (or lack thereof).
Overall, however, the formula is still clear. Diet plus exercise is still the best way to get healthy and lose weight. I provide many resources on how to lose weight on my website, and also have reviewed a number of workout programs to help you on your way.