Calories still count
It is becoming difficult to pick up a magazine or newspaper and not find some mention of the need to reduce daily dietary fat intake to 30 percent or less of calories. Numerous health and government authorities, including the U.S. Surgeon General, the National Academy of Sciences, the American Heart Association and the American Dietetic Association, advocate reducing dietary fat to 30 percent or less of total calories. Even the percentage of daily value of fat appearing on food labels is based on 30 percent of calories. But are Americans heeding these messages?
It appears that they are at least making some effort to reduce fat intake, according to a survey conducted by the U.S. Department of Agriculture (Continuing Survey of Food Intakes by Individuals, CSFII). This survey shows that from 1994 to 1996 the average American diet contained 33 percent of total calories from fat, down from 40 percent in 1978, which is extremely encouraging.
What is not encouraging, however, is the finding that Americans in general are seeing a heavier weight when they step on the scale. The National Center for Health Statistics found that, in the past decade, the proportion of U.S. adults who are overweight increased by eight percent — to 33 percent.
Other studies support these findings. A study from the National Institutes of Health confirms that in 1992-93, the average weight of Americans age 25-30 was 171 pounds. In 1985-86, the average weight was 161 pounds for the same age group.
Why then, if the percent of fat in the diet is decreasing, is obesity increasing? After all, fat has nine calories per gram while protein and carbohydrates only have four each.
The answer may not be a simple one. Experts believe a number of factors contribute to the increase in body weight. The continuing physical inactivity of Americans has been cited by numerous researchers as a major factor. Only 40 percent of Americans exercise on a regular basis. In addition, researchers point to such symptoms of a sedentary lifestyle as a 10 percent decline in sports participation from 1985-90, and a decline in manufacturing jobs, which means fewer people move around at work.
Other factors include a decrease in physical activity caused by television, a continuing increase in the usage of automobiles, and a decrease in physical education classes in schools. And these symptoms may be here to stay. “Experts agree that the root causes of obesity in the country — a sedentary lifestyle and an abundance of food — are very difficult to change,” says New York Times writer Marian Burros in a recent article on Americans’ weight gain.
Excess caloric intake, however, is also a factor. According to the latest National Health and Nutrition Examination Survey (NHANES), total caloric intake by adults increased from 1,969 calories in 1978 to 2,200 in 1990.
Obviously, calories still count! Weight is determined by the number of calories consumed and the number used as energy. If more calories are consumed than burned, the result is weight gain. Merely controlling grams of fat consumed, which was popular nutrition advice in the past, does not necessarily result in a reduction in calories.
As Dr. James Hill, with the Center for Human Nutrition at the University of Colorado Health Sciences Center, recently stated, “The idea that you can eat whatever you want as long as you don’t eat fat is totally wrong. There’s solid evidence that the composition of the diet is important, but it’s not just an issue of fat; total calories count too. So, yes, eat low fat. But don’t forget calories.”