A study released in the August issue of the American Journal of Clinical Nutrition (AJCN) provides a new understanding of almonds’ calorie count, showing they have about 20% fewer calories than originally thought. The study, conducted by United States Department of Agriculture (USDA) scientists, provides yet another reason to choose almonds as a nutritious snack.
At first glance, the study results beg the question, how can a food’s calorie count suddenly change when the composition of the food itself hasn’t?
The answer is that David Baer, PhD, and his team used an advanced method, built on traditional methods, to determine more precisely the number of calories from almonds that are actually absorbed during digestion. Resulting data showed a 28g serving of almonds (about 23 almonds) has 129 calories versus the 160 calories listed on labels.
The study’s discussion noted: “When an 84g serving of almonds was incorporated into the diet daily, the energy digestibility of the diet as a whole decreased by 5%.
Therefore, for individuals with energy intakes between 2,000 and 3,000kcal/d, incorporation of 84g almonds into the diet daily in exchange for highly digestible foods would result in a reduction of available energy of 100–150kcal/d. With a weight-reduction diet, this deficit could result in more than a pound of weight loss per month.”
The results support previous research indicating that the macronutrients in almonds, including fat, are only partially absorbed during digestion. The incomplete absorption of macronutrients in almonds is thought to be due to the fibre content and/or the rigidity of almond cell walls, which encapsulate macronutrients and render them unavailable for absorption during digestion. Therefore, traditional methods of calculating the energy value of almonds result in gross overestimations because they do not account for the fact that macronutrient digestibility in almonds are not 100%.
“I find the research about new, corrected calculations for almonds to be encouraging,” commented Dr. Geoff Livesey, registered public health nutritionist. “The Baer calorie study is an example of how a healthy, nutrient-dense food, like almonds, has 20% fewer calories than previously thought. I hope we see further research in the coming years to investigate more foods, in the context of a mixed diet, and their genuine caloric values.”
In fact, the same research team also recently conducted a similar study using pistachios, finding a 5% decrease in pistachios’ calorie count compared to the 20% decrease in almonds’.
Most often, foods’ calorie counts are calculated based on a system developed by Atwater et. Al more than 100 years ago. Known as the Atwater general factors, the system assigns calorie values for every gram of protein, fat and carbohydrate found in a given food (4cal/g for protein, 9 cal/g for fat and 4 cal/g for carbohydrate).
The recently published USDA study tested a healthy food, almonds, as part of a “mixed diet,” which means amongst other foods eaten as part of a normal diet. As the new study notes, “There have been few, if any, studies that looked at the calorie value of whole food within a mixed diet that could confirm the accuracy of Atwater’s coefficients.” So, for this study, the researchers expanded on Atwater’s approach, using a specially designed diet and a more precise method of measurement that allowed them to understand the calories provided by almonds when eaten as part of a mixed diet.
Almonds are nutrient-rich. Gram per gram, they contain more protein (6g), dietary fibre (3.5g), calcium (75g), vitamin E (7.4mg), riboflavin (0.3mg), and niacin (1mg) than any other tree nut. A 28 gram handful of almonds contain 13 grams of unsaturated fat, 1 gram of saturated fat and no cholesterol. Replacing saturated fats with unsaturated fats in the diet contributes to the maintenance of normal blood cholesterol levels.
Source: Confectionery Production