Obesity: Is Diet or Activity More Important?
Updated November 07, 2013.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.
Question: Obesity: Is Diet or Activity More Important?
I'm trying to lose weight, and I'm getting confused about whether I should concentrate on what I eat or how much exercise I get. Which is it?
Answer:
Your confusion about whether to focus on diet or exercise is understandable.
Recent studies almost appear designed to generate misunderstanding about which is the main cause of becoming overweight -- the amount of food we consume, or the amount of exercise we get.
In one study that made headlines, investigators reported that it is the increasing amount of food Americans eat, and not reduced activity levels, that is responsible for the "obesity epidemic" said to be occurring in the United States. To reach this conclusion, researchers used food supply data from the U.S. Department of Agriculture (to determine how much food was provided to Americans between 1970 and 2002), and applied to that data a number of equations that took into account body size, energy expenditures, and activity levels in a sampling of American adults and children.
From such mathematical modeling, they find little to suggest that Americans are really exercising less; rather, they're eating more. So, these researchers say, the increases we've seen in Americans' average weight (in both adults and children) over the past several decades can be explained solely by an increase in the amount of food we eat.
On the other hand, another study appears to suggest the opposite -- that the amount of exercise we get is extremely important in determining our weight.
This study shows that a new style of cardiac rehabilitation program, aimed at burning lots of calories, results in better and more sustained weight loss than the standard kind if cardiac rehab -- thus, demonstrating the importance of activity in producing weight loss.
This new variety of cardiac rehab, called "high-calorie-expenditure exercise," emphasizes sustained, low-intensity exercise aimed at burning as many calories as possible. Specifically, the program emphasizes walking at a moderate pace for at least 45 to 60 minutes per day, at least 5 to 6 days a week. For most individuals, this program will result in burning an "extra" 3000 t0 3500 calories weekly, which translates to nearly 1 pound of weight per week. (Typical rehab programs of shorter, higher-intensity exercise result in about 800 calories burned per week.) This new kind of rehab program also emphasizes counting (and limiting) the number of calories eaten, so that the overall result is designed to be a sustainable loss of weight.
In a small clinical trial involving 74 patients with significant coronary artery disease, those receiving the "calorie-burning" variety of cardiac rehab lost more weight, more total fat, and more abdominal fat (and more waist circumference) than those receiving the standard form of cardiac rehab, and had a significantly greater improvement in their cardiovascular risk profile (including cholesterol values). The significant improvement in cardiac risk persisted for the 1-year follow-up evaluation.
So one headline-grabbing study says it's what you eat, and another headline-grabbing study says it's what you do.
Any change in your weight is the result of a simple calculation: the total calories you gain (or lose) equals the number of calories you consume minus the number of calories you burn. It's that simple.
So anyone who suggests that the only thing that's important is either the amount of food you eat, or the amount of exercise you get, is either being naive or deceptive. Obviously, if you want to lose weight, you need to both cut down on the calories you put into your mouth and increase the number of calories you burn on a daily basis. This is why counting calories (both in and out) can give you a lot of useful feedback on which aspect of weight loss you, yourself, need to work on the most.
You can get a little help with your calorie watching efforts (for free) by checking out Calorie Count, a part of About.com.
And here's some valuable guidance on beginning your own walking program.
Sources:
Ades PA, Savage PD, Toth MJ, et al. High-calorie-expenditure exercise. A new approach to cardiac rehabilitation for overweight coronary patients. Circulation 2009; DOI: 10.1161/CIRCULATIONAHA.108.834184.
Swinburn B. Increased energy intake alone virtually explains all the increase in body weight in the United States from the 1970s to the 2000s. 2009 European Congress on Obesity; May 6-9, 2009; Amsterdam, the Netherlands. Abstract T1:RS3.3.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.
Question: Obesity: Is Diet or Activity More Important?
I'm trying to lose weight, and I'm getting confused about whether I should concentrate on what I eat or how much exercise I get. Which is it?
Answer:
Your confusion about whether to focus on diet or exercise is understandable.
Recent studies almost appear designed to generate misunderstanding about which is the main cause of becoming overweight -- the amount of food we consume, or the amount of exercise we get.
In one study that made headlines, investigators reported that it is the increasing amount of food Americans eat, and not reduced activity levels, that is responsible for the "obesity epidemic" said to be occurring in the United States. To reach this conclusion, researchers used food supply data from the U.S. Department of Agriculture (to determine how much food was provided to Americans between 1970 and 2002), and applied to that data a number of equations that took into account body size, energy expenditures, and activity levels in a sampling of American adults and children.
From such mathematical modeling, they find little to suggest that Americans are really exercising less; rather, they're eating more. So, these researchers say, the increases we've seen in Americans' average weight (in both adults and children) over the past several decades can be explained solely by an increase in the amount of food we eat.
On the other hand, another study appears to suggest the opposite -- that the amount of exercise we get is extremely important in determining our weight.
This study shows that a new style of cardiac rehabilitation program, aimed at burning lots of calories, results in better and more sustained weight loss than the standard kind if cardiac rehab -- thus, demonstrating the importance of activity in producing weight loss.
This new variety of cardiac rehab, called "high-calorie-expenditure exercise," emphasizes sustained, low-intensity exercise aimed at burning as many calories as possible. Specifically, the program emphasizes walking at a moderate pace for at least 45 to 60 minutes per day, at least 5 to 6 days a week. For most individuals, this program will result in burning an "extra" 3000 t0 3500 calories weekly, which translates to nearly 1 pound of weight per week. (Typical rehab programs of shorter, higher-intensity exercise result in about 800 calories burned per week.) This new kind of rehab program also emphasizes counting (and limiting) the number of calories eaten, so that the overall result is designed to be a sustainable loss of weight.
In a small clinical trial involving 74 patients with significant coronary artery disease, those receiving the "calorie-burning" variety of cardiac rehab lost more weight, more total fat, and more abdominal fat (and more waist circumference) than those receiving the standard form of cardiac rehab, and had a significantly greater improvement in their cardiovascular risk profile (including cholesterol values). The significant improvement in cardiac risk persisted for the 1-year follow-up evaluation.
So one headline-grabbing study says it's what you eat, and another headline-grabbing study says it's what you do.
So What's the Bottom Line? Food or Exercise?
Obviously, it's both.Any change in your weight is the result of a simple calculation: the total calories you gain (or lose) equals the number of calories you consume minus the number of calories you burn. It's that simple.
So anyone who suggests that the only thing that's important is either the amount of food you eat, or the amount of exercise you get, is either being naive or deceptive. Obviously, if you want to lose weight, you need to both cut down on the calories you put into your mouth and increase the number of calories you burn on a daily basis. This is why counting calories (both in and out) can give you a lot of useful feedback on which aspect of weight loss you, yourself, need to work on the most.
You can get a little help with your calorie watching efforts (for free) by checking out Calorie Count, a part of About.com.
And here's some valuable guidance on beginning your own walking program.
Sources:
Ades PA, Savage PD, Toth MJ, et al. High-calorie-expenditure exercise. A new approach to cardiac rehabilitation for overweight coronary patients. Circulation 2009; DOI: 10.1161/CIRCULATIONAHA.108.834184.
Swinburn B. Increased energy intake alone virtually explains all the increase in body weight in the United States from the 1970s to the 2000s. 2009 European Congress on Obesity; May 6-9, 2009; Amsterdam, the Netherlands. Abstract T1:RS3.3.
