Walnuts have 21 per cent fewer calories: USDA

In a significant find for the calorie-conscious, researchers today said walnuts have 21 per cent fewer calories than what is currently assigned by US government to the 'king of nuts'.
A new study published in the prestigious Journal of Nutrition found that walnuts have 21 per cent fewer calories than what is currently assigned by the United States Department of Agriculture (USDA).
The study led by Dr David J Baer, Supervisory Research Physiologist at the USDA shows that one serving (1 ounce or 28.35 grams) of walnuts contains 146 calories, not 185, which is 39 calories less than the value currently used.

Historically, the calorie value for walnuts was determined using the Atwater factors, which were developed in the late 19th century and calculate metabolisable energy, or energy available to the body, for many foods.
Baer's research found that the metabolisable energy of walnuts was 21 per cent less than that predicted by the Atwater factors.
"Yes, these are significant results in the sense that they provide, for the first time, an accurate measure of the number of calories in a serving of walnuts. This research overcomes limitations of research conducted over 100 years ago whose results are still used today," Baer told PTI.

"Our results could help explain why consumers of walnuts do not typically gain weight. And given the numerous potential health benefits of consuming walnuts, including reduced risk for cancer, cardiovascular and cognitive diseases, our results could potentially help alleviate any calorie-related concerns consumers might have with incorporating them into their everyday diet," Baer said.

He said that there are many aspects of a food to consider when one decides what and how much to eat.
"High fat foods do not necessarily make us fat and low fat foods are not necessarily the healthiest for us to eat. We have to consider the availability of calories when making food choices, especially for tree nuts," Baer said.

"Walnuts are a good or excellent source of several important nutrients. However, some consumers might be reluctant to include walnuts in their diet for fear that consuming walnuts might lead to weight gain.
"For those calorie-conscious consumers who might avoid walnuts, our results show that the number of calories in a serving of walnuts is significantly less that what is currently on the food label, he said.
Commenting on the health benefits of walnuts, Dr H K
Chopra, President of Cardiological Society of India said, "Walnuts are one of the richest sources of omega-3 fatty acids, with 2.5 grams of alpha-linolenic acid (ALA) per serving. Several studies have suggested that regular consumption of walnuts helps in effective weight management.

"Any successful weight management plan must include satiety factor and owing to the high fibre content, walnut is undoubtedly the right food to consider if you are into a weight management programme."
Naini Setalvad, Nutritionist and health consultant said, "Consuming a diet comprised of walnuts is the key to healthy living. Incorporating walnuts into meals and snacks is a simple, delectable and convenient way to help ensure adequate protein intake, especially among vegetarians.
One ounce of walnuts provides four grams of protein, and two grams of fibre. The fibre aspect helps make you feel full, promotes weight management, and can assist in lowering cholesterol and regulating blood glucose levels."

To reach their conclusion, Baer and his research team studied 18 healthy adults. Each person was assigned randomly to a sequence of two diets: a controlled American diet without walnuts for a 3-week period, and a controlled diet with 1.5 servings of walnuts (42 grams) for another 3-week period.
Total calorie levels were consistent for individual participants across both treatment periods. Administered diets, walnuts, fecal and urine samples were collected and subject to bomb calorimetry, to measure calories, and the resulting data were used to calculate the metabolisable energy of the walnuts.
The study provides insight into the growing body of research supporting the beneficial role walnuts play in weight management.

In addition to providing a convenient source of fibre (2 grams per ounce) and protein (4 grams per ounce), walnuts are the only nut that contain a significant source of alpha-linolenic acid (2.5 grams per ounce), a plant-based omega-3 fatty acid with heart and brain-health benefits.
Further research is needed to better understand the results of the study and how this technique for calculating calories could potentially affect the calorie count of other foods, Baer said.
The study was supported in part by funds from the USDA and the California Walnut Commission.