Recently, a female patient of mine expressed her frustration at being unable to lose weight despite exercising more and increasing her overall physical activity. Her story is not atypical. Exercise is important in weight loss, but it is not the most important weight loss factor. Yet, it is the one that most individuals think is the key weight loss factor.
Well, if exercise is not the most important weight loss factor, what is? Nutrition is the most important weight loss factor. Yet, in my experience it is easier to get people to exercise than it is to get people to change what and how they eat. But, we should not forget that there are plenty of other good reasons to exercise even if it may have limited effect on weight loss.
Exercise: Important but not the Most Important Weight Loss Factor
We have said before that weight loss is more than a simple equation where calories in equals calories out. But, if we look at weight loss from just a calorie perspective we can see why exercise is not the most important weight loss factor. There are 3,500 calories in a pound. Including our basal metabolism we burn approximately 0.75 calories per pound of body weight per mile we run. So a 150 pound runner burns 2,948 calories during a marathon (26.2 miles). Not even a pound is burned. That shows you how much exercise you need to do to lose a single pound.
Here’s another example, this one from Gary Taubes’ book Why We Get Fat. A 250 pound man would have to climb 20 flights of stairs to burn the calories found in a slice of bread. That’s pretty disheartening to learn that. It is simply easier to avoid the slice of bread and use the time climbing stairs for something else.
To get a better appreciation of the number of calories burned doing different physical activity go to this link.
Nutrition: the Most Important Weight Loss Factor
What and how we eat determines better if we will lose or gain weight than exercise. We think of insulin as the hormone that regulates blood sugar, which it certainly does. But, insulin also controls how much fat we have. Insulin promotes fat storage and prevents calories from being burned from fat stores. How much insulin we have in our bloodstream at any given time is directly dependent on what we eat and how we eat. Eating foods with simple sugars or only eating carbohydrates without fat or protein can lead to excessive spikes in blood sugar and insulin.
Foods that are low glycemic will not cause a spike in insulin and will allow the burning of calories from fat. Also, pairing any carbohydrate with a fat or protein source delays the absorption of glucose into the bloodstream and blunts the rise of insulin.
Eating throughout the day keeps energy levels relatively constant and avoids rapid swings in blood glucose and insulin levels. So eating snacks in between meals will prevent hunger pangs and a tendency to overeat during the major meals of the day that lead to excessive insulin levels.
Hormones: Another Key Weight Loss Factor
Hormones are another key weight loss factor. We’re talking primarily sex hormones in both men and women. Both men and women gain fat and lose muscle mass as their sex hormones decline. Sex hormones improve insulin sensitivity and prevent fat storage of calories when in proper balance. By maintaining lean body mass optimal hormone levels improve metabolism facilitating weight loss.
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