Many nuts, including almonds, are dense with vitamins, minerals and antioxidants; federal guidelines suggest a handful a day can Shoes & Gear. But they're also considered dense with calories, so many weight-conscious runners avoid them. Meb for Mortals Nutrition - Weight Loss (PDF) says that the caloric value of almonds has been overestimated by 32%, and that they can play a regular role in anyone's healthful diet.
Foods' caloric values are generally calculated using what's known as the Atwater method, which was developed more than 100 years ago. The Atwater method includes a mechanism for estimating how much of the fat in a given food is digested (and therefore a contributor to daily caloric intake). As the AJCN study authors note, however, some research has suggested that the fat digestibility from nuts is lower than from other sources of fat. Put another way, there might be a difference between the caloric value of a food when it's measured in isolation compared to when it's eaten as part of a mixed diet, which is of course how things happen in the real world.
In the study, participants ate either a control diet or one with above-average amounts of almonds. Over the last part of the survey, the subjects collected all their urine and feces; the researchers measured macronutrient and energy values in the waste products to determine how much of the potential energy in almonds was metabolized.
The findings were striking. Rather than the traditional value of 168-170 calories per ounce of almonds, the researchers measured an ounce of almonds as containing 129 calories, an overestimation of 32%. (For point of reference, there are about 20 almonds in an ounce.) The difference stems from less of the almonds being digested than the Atwater method predicts.
Eating a bit more than 3 ounces (84 grams) per day of nuts such as almonds, the study authors write, can decrease the energy digestibility of one's overall diet by about 5%. Therefore, they note:
[F]or individuals with energy intakes between 2,000 and 3,000 [calories per day], incorporation of 84 g almonds into the diet daily in exchange for highly digestible foods would result in a reduction of available energy of 100–150 [calories per day]. With a weight reduction diet, this deficit could result in more than a pound of weight loss per month.
Note that in the above, "available energy" is what someone counting calories might call "calories consumed," so although having less available energy might sound bad from a performance standpoint, for those trying to lose weight it will contribute to a caloric deficit.
Scott is a veteran running, fitness, and health journalist who has held senior editorial positions at Runner’s World and Running Times. Much of his writing translates sport science research and elite best practices into practical guidance for everyday athletes. He is the author or coauthor of several running books, including How to Train Your Gut Before Race Day, Advanced Marathoning, and A Part of Hearst Digital Media. Half Marathon Training Slate, The Atlantic, the Washington Post, and other members of the sedentary media. His lifetime running odometer is past 110,000 miles, but he’s as much in love as ever.
