Here’s another great article from Fooducate!
Losing weight means counting calories. We all know that weight loss is a simple mathematical equation: calories eaten minus calories burned. However, real life is a bit more complicated.
Here’s a list of problems we have with counting calories:
1. Packaged food calorie labels are inaccurate. According to FDA regulations, calorie information on packages must be accurate with a margin of error of 20%. Which means you could be off by as much as 100 calories on a 500 calorie entree. Statistically, you would expect some products to be over, and others under, adding up to a zero-sum error. However, most manufacturers err towards the plus side.
2. Portion size incorrect. Most people have no idea if the portion they are eating is what the label says. Take breakfast cereal for example. A serving is usually just 1 ounce, but people fill a bowl with 2 or even 3 ounces. If you are counting calories but log a portion that is too small, your daily log will underreport your actual consumption.
3. Calorimeters are not good models of the digestive tract. A calorimeter measures the energy in a food by burning it. Comparing the temperature difference before and after the burn gives an estimate of the calories in the food. However, humans don’t extract every calorie of energy from the food we eat. Take almonds and walnuts for example; some of the fiber in these nuts is indigestible, and as a result, the actual energy we obtain from them is lower than the stated calorie count.
4. Calorie availability depends of processing method. Generally speaking, cooking or otherwise heating food makes more calories available to the digestive tract. A rare steak will offer less calories compared to the same cut, well done.
5. Difference in gut microbiome amongst individuals. The human gut is home to trillions of bacteria that have evolved alongside humans and aid in digestion. There are several thousands of bacteria species, and every human is a home to a unique combination. Some bacteria are much more effective at extracting energy from food compared to others. If you tend to gain weight while your friend who eats exactly the same food sheds the pounds, the difference between the two of you may be intestinal bacteria.
Does all this mean you should give up and stop counting calories?
No. Even with all these shortcomings, people who count calories lose twice as much weight as those who don’t, and more importantly, keep the weight off for a longer period of time.