How are you supposed to lose weight if the calorie values you’re using to track your food intake are all wrong? This is an excellent question, and one that is being asked by several prominent researchers from Harvard and elsewhere. But, surely the question on your mind is, what does that mean for me?
Bottom line: Calorie counting is not an exact science.
But wait, there’s more! These studies are actually calling into question the Atwater system, the century-old model that assigns 4 calories per gram to carbohydrates and proteins and 9 calories per gram to fats for the purposes of determining total caloric value (Note: alcohol is 7 calories per gram).
Where’s fiber in this equation?
One of their primary concerns is the fact that fiber, particularly soluble fiber, does in fact contribute calories, but is ignored in the calculations. Fiber actually comes in at about 2 calories per gram on average, which could certainly skew your weight loss efforts over time, especially if you’re a fiber aficionado.
Let’s face it—this is a legitimate beef (no pun intended) and should be communicated to the general public. But that’s not all.
These researchers point to other issues that may alter calorie counts even more…
- Our bodies extract more nutrients and calories from cooked or processed foods.
- Refined carbohydrates make people hungrier than the equivalent amount of whole grains, resulting in overeating.
- Calorie counts ignore the 5-30% of energy used for the digestion and absorption of a given food.
- Some foods contribute fewer calories because we don’t chew them well enough to release all of the nutrients.
Cooking actually increases nutrient availability
Processing and cooking do in fact increase the energy availability of some foods. And there are plenty of other variables not accounted for by the Atwater values that could throw off the calorie counts for specific items.
As mentioned, the energy needed to digest foods is an important factor, and this includes chewing, the secretion of acids and enzymes, peristalsis (intestinal movement), and the production of heat after eating (the thermic effect of food). Add to this the fact that gut bacteria can consume some of our calories as well, and you’ve got the makings of a notable discrepancy between what the food label says and what your body is actually utilizing as energy.
The Atwater system simplifies the process
Proponents of the Atwater system argue that, when looking at someone’s total daily diet, the system is unlikely to introduce a lot of error—something less than 5% on average. And because the various factors mentioned above complicate things greatly, the Atwater system does a good job of simplifying the process. In other words, the values are appropriate for most foods in most diets. There’s also a silver lining here. Most of the variables missed with the Atwater system actually lead to overestimates of caloric value, so those looking to lose weight aren’t adversely affected.
It’s important to note that, because of differences between individuals, it would be difficult to create a system that would work for everyone. But according to the researchers, it doesn’t mean we shouldn’t try. They plan to put out a white paper in the coming months.