How walnuts can help control appetite

Walnut, the single-seeded stone fruit, is rich in omega-3 fats, protein, antioxidants, plant sterols, magnesium, copper, Vitamins A, D, etc. Consumption of walnuts suppresses your hunger. It makes you feel fuller for a longer duration thereby helping you in your weight loss trail. Researchers used functional magnetic resonance imaging (fMRI) to observe how consuming walnuts changes activity in the brain.

They recruited 10 volunteers with obesity for two five- day sessions. A controlled environment allowed researchers to keep tabs on the volunteers' exact nutritional intake, rather than depend on volunteers' often unreliable food records.

During one five-day session, volunteers consumed daily smoothies containing 48 grammes of walnuts. During their other stay in the clinic, they received a walnut-free but nutritionally comparable placebo smoothie, flavoured to taste exactly the same as the walnut-containing smoothie. Researchers noted that participants reported feeling less hungry during the week they consumed walnut-containing smoothies than during the week they were given the placebo smoothies.

Specific hormones in the body help control appetite. Some hormones are responsible for signalling the body to eat, whereas others tell the body it is full, or satiated. Eating food rich in PUFAs, like walnuts, can influence the appetite hormones so that one can feel fuller for longer. Adding that appetite hormones play an important role in regulating how much an individual eats. Other foods rich in PUFAs include oily fish such as salmon and corn, grapeseed or canola oil. The control diet was comprised of 7% polyunsaturated fat, 15% monounsaturated fat and 13% saturated fat, compared to the PUFA-rich diet which was 21% polyunsaturated fat.

While in the machine, participants were shown images of desirable foods like hamburgers and desserts, neutral objects like flowers and rocks, and less desirable foods like vegetables. When participants were shown pictures of highly desirable foods, fMRI imaging revealed increased activity in a part of the brain called the right insula after participants had consumed the five-day walnut-rich diet compared to when they had not.

"This is a powerful measure. We know there is no ambiguity in terms of study results. When participants eat walnuts, this part of their brain lights up, and we know that is connected with what they are telling us about feeling less hungry or more full," said Christos Mantzoros, professor of medicine at Harvard University in the US.

This area of the insula is likely involved in cognitive control and salience, meaning that participants were paying more attention to food choices and selecting the less desirable or healthier options over the highly desirable or less healthy options, researchers said.

When purchasing unshelled walnuts, one should avoid those with a rubbery or shrivelled appearance. Because walnuts turn rancid fairly quickly, shelled nuts should be kept in an airtight container and placed in the refrigerator, where they can keep for six months, or in the freezer, where they'll stay fresh up to a year. Unshelled walnuts will keep fresh in any cool, dry location for six months. To preserve flavor and nutrients, avoid chopping nuts until you're actually ready to use them.

Walnuts are high calorie content food item. So one must be careful in how much they eat. Having given that warning, it is almost impossible to eat too many walnuts daily. A four ounce of walnut consumption will provide full requirement of daily fat content. The overall impact is on your weight. When the health of your heart is improved, inflammations are removed and diabetes is controlled, it must reduce weight.