“Eat less,” we are told,” to lose weight.” But less than what? Well, I guess than what we are eating now. But we don’t necessarily overeat every day. And, if we eat too little, we get powerful sensations of hunger which we satisfy with food. So, how many calories should we be eating? The minimum amount is what our bodies need to function. This is called the resting metabolic rate (RMR) or the basal metabolic rate (BMR). It can be measured quite precisely in the laboratory but most dieters won’t have that option. For many years, algorithms have been developed and refined to make the determination easier. Quite a few are available on the Internet. While writing up a new research paper on the importance of the RMR, I decided to check out the web calculators. I googled “how many calories should I eat” and got a number of health-diet related websites. Some are quite well known, others less so. Most asked for the same information: Gender, age, weight and levels of physical activity. What I got back was quite stunning.
The sites that came up first in the Google search, about 10, gave me a range of RMR from a low of 1973 to a high of 2851.
Then I looked at some highly regarded health care associations. Here, I really had to search hard, often going to “resting metabolic rate calculator” as the search term. The American Heart Association’s calculator gave me a RMR of 3430, the American Diabetes Association 2400. And the winner is… the American Cancer Society gave me a whopping 4696 to maintain my current weight.
Most federal government sites on obesity, healthy eating did not have a calculator. Most referred me to the ChooseMyPlate site of the Department of Agriculture (www.choosemyplate.gov). This site is the consumer version of the Dietary Guidelines for All Americans. After 5 clicks or so, I found the calculator which gave 2400 as my base calorie intake figure.
Who is right? Who knows? The range in this un-scientific study is 2,723…enough for another adult person entirely. Remember, if one eats just 10 calories a day over their RMR, they will gain a pound in one year; ten pounds in a decade. So the margin of error is very small to begin with. The point is this: One’s basal metabolic rate is a key number for any weight loss effort. None of these sites indicated that their calculators were estimates or that the numbers could vary. Is it any wonder that some many people fail in weight management when the starting number is so open to error?