We Aren’t Eating More; We are Exercising Less
~ September 1999 No.78 ~
It goes against what many experts have been telling us for a long time and it may be bad news for all of those “no fat” products, but nutritionist Dr. Alison Steven (University of Saskatchewan, in Saskatoon, Canada) says that her review of the literature shows that the average caloric intake of North Americans is slowly going down.
Dr. Steven has looked at diet surveys carried out over the last fifty years in which people were asked what they ate - usually in the past three days. Such diet recall studies are often criticized as being unreliable, because it is generally believed that people (intentionally or unconciously) under report what they have eaten. For people who have a hard time remembering what they had for lunch just a few hours ago, it is easy to understand how things could get left off the list. But, as Dr. Steven argues, there is no reason to believe that the under-reporting in the most recent studies should be any worse than in the earlier studies.
So how does she explain the rise in obesity ? It’s a simple matter of energy from the diet in and energy used during exercise and for metabolism out. To a nutritionist the weight gain problem is simple to explain if we are taking more calories in than we are burning up, the excess becomes body fat. If the amount of calories we eat is going down - as Dr. Steven believes - and we are still putting on fat, that can only mean that we are not burning up enough calories. So it is not illogical to say that North Americans are getting fatter while at the same time they are eating fewer calories.
It is perhaps too early to say whether the trend that Dr. Steven has seen in her analysis of the data is significant or not. But it is evident that just cutting down on high fat foods and replacing fatty foods by ones that are high in carbohydrates is not enough if you are going to reward yourself with an extra hour in front of the television. Yes calories count - the ones we eat and the ones we burn off when we exercise.
|1 bottle of beer:||145|
|100 g of french fries:||200|
|100 g vanilla ice cream:||201|
|data from USDA National Nutrient Database|
|1 hour of tennis:||508|
|1 hour of slow walking:||159|
|1 hour of aerobics:||381|
|1 hour of curling:||254|
|1 hour of golf (carrying clubs):||350|
|data from NutriStrategy - applicable to a body weight of 64 kg or 140 lb|