The skinny on almonds
When is a 100-calorie pack not a 100-calorie pack? When it's filled with almonds.
The calorie count for California almonds turns out to be 20 percent lower than previously measured, according to new studies conducted by nutrition scientists at the U.S. Department of Agriculture.
So that 100-calorie pack of dry roasted almonds you might grab to snack on actually contains 80 calories. The almonds are not any different, but the way the USDA calculates calorie content is new and improved.
Historically, samples of food are burned in the lab to measure the amount of heat given off, which is measured in calories.
Now USDA researchers have enlisted the help of human volunteers to determine the number of calories actually digested and absorbed from almonds as part of typical American meals.
"We are excited to have this approach to look at calories in a mixed diet," said David Baer, who led the research study published this month in The American Journal of Clinical Nutrition. "How we count calories is an important issue."
Like a GPS system, USDA nutrition experts are recalculating, and their new course is a bit more complicated because measuring digestion and absorption in human volunteers means collecting samples of feces.
The analysis revealed that the fat in almonds is not absorbed as easily as fat in other foods due to the nut's fiber content.
"Fat is stored inside the cell walls," said Chris Rosenbloom, a registered dietitian and professor emerita of nutrition at Georgia State University.
"If the cell walls are not completely broken down through chewing and normal digestion, then not all of the fats, therefore not all of the calories, will be available to the body.
"So foods like almonds that are high in fiber and a 'hard' nut actually have fewer calories based on the usual calculations." Similar studies with pistachios found 5 percent fewer calories than previously measured.
Another diet discovery: Even though subjects were fed meals designed to maintain their weight during the USDA study and were consuming about 70 almonds a day, many lost weight because the available amount of calories was actually 100 or 150 calories fewer per day because 20 percent of the nut was not being digested.
"So if you avoid almonds because of the calories, you should think again," Rosenbloom said. "Almonds can help you feel full longer so (they) are good food to include for weight management."
Scientists report that the more almonds are chewed up or chopped into slivers or pureed into almond butter, the easier they are to digest and therefore are higher in the ultimate calorie count.
"This new research opens the door for scientists to take a fresh look at how the body uses the energy stored in foods," Rosenbloom said. "So a calorie may not be calorie -- at least as far as the food label goes."