A lot of people ask two questions: 1. How much of weight loss comes from diet? and; 2. How much of weight loss comes from exercise? These are very good questions. While important, they ignore another component – genetics. Our DNA certainly plays a key role in the size and build of a person. In our family, I have really seen how this is manifested in our children. Even with the same parents, not all of our children are built the same. So, after considering the genetic aspect, then it comes down to diet and exercise, which are the two components we can control. While it might be easy to assume that it would be about 50/50 (diet/exercise), I think it is really more like 70/30, which is why I call this the “Rule of 70”.
The Rule of 70 holds true for a few reasons. First, the dietary component is more controllable. Exercise is more variable, and often dependent on our circumstances. There are times in our lives when it is easy to fit in exercise. There are other times, when due to external things like injuries, aging, or duties in life that it is difficult to maintain consistent exercise. In those times, our diets better be pretty good if we want to maintain our weight, and certainly if we want to lose weight.
A second reason I believe it is more like 70/30 is that if one of the factors depends on the other, it is exercise that depends on diet (or nutrition). If we are not eating well, it is much harder to maintain fitness. We feel tired, heavy, and lethargic, and our workouts are not as effective.
Finally, diet is more clear cut…. It is hard and fast; for every 3500 calorie deficit (the amount we burn minus the amount we consume), we lose one pound. A pound of body fat equates to approximately 3500 calories. According to Calories per Hour.com, if you have a calorie deficit of 500 calories (meaning that you burn 500 calories more than you eat each day) you would lose approximately one pound of fat per week. That is no matter how you burn it, even living a sedentary lifestyle.
It takes more effort to rely on exercise for weight loss than to rely on our diet. That is definitely not to say that I think it is wise to maintain or lose weight by nutrition (diet alone). Fitness is a crucial part of this picture. Frankly, in the end, it is the fitness component that provides strength, giving a person the “fit” or “toned” look that many desire.
When someone asks me what percentage of weight loss (or even weight maintenance) is diet and what percent is exercise, my answer is that it is the Rule of 70…about 70% is diet and about 30% is exercise.
What are your thoughts about the diet/exercise factors involved in losing (or maintaining) our weight?