Walnuts as a Source of Dietary Choice for Weight Loss & Cardiovascular Health Protection

Walnuts Work Wonders on your Mind & Body

Dieting is not starving or distancing yourself from all the delicious, interesting and calorie-laden foods. Indeed, it involves maximum consumption of fruits, vegetables and whole grains but you get to eat your share of low-fat dairy, proteins, lean meats and nuts for a balanced meal. Even desserts and mithai can be occasionally included to overcome the boredom and monotony of your diet plan. Maybe, call this even your cheat meal once a week. If we look at our daily diet plan that includes different foods, nuts do occupy a prominent place contributing a major chunk of calories and good health too. They are a great snacking option and can also be an interesting salad dressing.
​
Obesity and overweight issues dominate our lives for which healthy lifestyle changes, regular exercise schedules, good sleep and a balanced diet are essential to guard us. Different diets are proposed for achieving weight loss and the Mediterranean diet is a critical one. Apart from fruits, veggies, whole grains and olive oil, nuts form an indispensable part of this diet plan. Evidences show that nuts fight against the risk of cardiovascular diseases, sudden death and diabetes mellitus which are the effect of improved lipid profile, inflammation and endothelial function. Creating energy deficits between calories consumed and burned is the basis of effective weight loss. Nuts are rich in fats and hence are considered as potential sources of positive energy balance and hence, many people avoid consuming it while on a weight-loss diet. But evidences are showing us a different perspective regarding nut consumption. Nuts are not associated with a higher body weight and epidemiological evidence indicate that nut consumption is rather associated with a lower BMI than in those who don’t consume it.

Don’t Give If’s & But’s with Nut’s Effect on Weight Loss Intervention
There are evidences showing the effect of pistachios, almonds, peanuts and walnuts on weight changes, weight loss interventions and risk of cardiovascular diseases. These nuts help the individual feel satiated for a longer period of time thereby reducing total energy intake and feelings of hunger. Many of these studies did not focus on the effect of walnuts on the symptoms such as hunger, fullness and satiety and in those diets that did include walnuts, volunteers started feeling satisfied after the second day of the meal.
​
A research group focused mainly on walnuts and their effects on weight loss. This group compared the effects of a walnut-enriched reduced-energy diet to a standard reduced-energy-density diet on body weight changes and cardiovascular disease risk from obese/overweight individuals during a 6-months weight loss intervention program. The research team shortlisted 100 volunteers based on selection criteria such as BMI between 27 and 40, aged above 21 years, willing to answer questions over phone or personally, not allergic to tree nuts and willing to allow for blood sample collection. Those who abstained from exercise due to some disability, planning for pregnancy, breastfeeding or having a history of a psychiatric condition were excluded from the study. Each participant met a dietitian and was given a sample meal plan depending on the participant’s goals and food choices. The scientists prepared the diet with an aim of creating 500-1000kcal/day of deficit. The participants were randomly assigned to one of the two diet plans prescribed: standard reduced-energy-dense diet that contained fruits, veggies, whole grains, lean protein sources and low-fat dairy with the complete exclusion of nuts and those assigned to the walnut diet plan were requested to consume 42 g of walnuts/day for diets that were >1500 kcal/day and 28 g of walnuts/day for diets <1500 kcal/day.

Every participant was requested to weigh himself/herself daily, an activity tracker helps them fulfill their 10000-steps a day of activity daily within a month and improve their lifestyle activities. Apart from this, each of them was required to do 60 minutes of moderate-intensity aerobic activity and at least 2-3 days of strength training activity. Participants were asked to rate satiety with the help of three specific questions:

1. How hungry are you? With its answer from “I have never been more hungry: (scored as 0) to “I am not hungry at all” (scored as 100)
2. How full do you feel? With its answer from “Not at al full” (scored as 0) to “Totally full” (scored as 100)
3. How much do you think you could eat now? With answer from “Nothing at all” (scored as 0) to “A lot” (scored as 100)
   
   

Results showed that:
​

• Both the groups demonstrated a reduction in body weight, BMI and waist circumference
• Both the groups dropped their systolic blood pressure at 3 months but only the walnut-enriched group maintained this drop at 6 months comparatively
• Both groups had a decrease in diastolic blood pressure during the 3rd and 6th month and also increased their physical activity
• Cardiopulmonary fitness improved in both study groups
• Volunteers assigned to the walnut-enriched group and not the standard reduced-energy-density group had reductions in total cholesterol levels at 6 months. Triglycerides decreased at 3 months in the standard group and at 6 months in both the group and HDL did not show any changes between 0 and 6 months in either of the groups.
• Individuals >50 years of age decreased their cholesterol by 2 mg/dL compared to a decrease of 19 mg/dL in subjects younger than 50 years.
• Volunteers who lost ≥5% of initial body weight decreased their cholesterol by an average of 13 mg/dL compared to an increase in cholesterol of 18 mg/dL in those participants who did not lose at least 5% of initial body weight.
• Feelings of fullness and hunger was higher in the standard diet at week 12 compared to week 1 but feelings of fullness were lower in the walnut-rich diet at week 12
  
  

While weight loss was associated with improvements in lipids and blood pressure in both the diets, the walnut-enriched diet showed more inclination towards reduced risk of cardiovascular disease risk. Hence, a walnut-enriched diet can promote weight loss equally good as a standard diet without nuts. Walnut-enriched diet has an advantageous edge in that it promotes more favorable effects on LDL-C and systolic blood pressure comparatively.

Improved Lipid Profiles
Walnuts are especially favored for reducing coronary heart disease risk and with their high content of polyunsaturated fatty acids they can improve overall dietary fatty acid profile, deliver dietary phytosterols and fiber. Evidences exist showing that walnuts improve lipid profiles too. Another study tested the effect of walnut consumption on weight loss. It randomly assigned the participants (whose BMI was between 25 and 40) into one of the three diets: general dietary advice (C), individualized dietary advice (I) or interdisciplinary intervention plus 30g walnuts/day (IW). The study showed significant difference in weight loss between the three groups. Over the 12-month span, participants in the IW group achieved maximum weight loss and weight loss was greater in the IW group than C. No significant difference in weight loss was detected between IW and I group nor between I and C groups over the entire research period. The walnut group achieved excellent diet quality by increasing energy intake from fruits and vegetables while decreasing energy intake from discretionary foods/beverages. Including a high-nutrient food such as walnuts enhances nutrition levels and enables weight loss. Alongside diet, doing physical activity and following lifestyle changes help in sustaining the weight loss over a long time.

A meta-analysis of more than 20 trials on blood lipids and cardiovascular risk factors showed that walnut-enriched diets showed excellent reduction in blood lipid levels compared to the Western diets but no significant differences in weight reductions or blood pressure levels were noticed due to a walnut-enriched diet.

Energy-dense foods must be carefully controlled for weight loss and maintenance of weight loss. Nuts are a primary source of energy-dense foods but 55-75% of energy contributed by nuts is offset by dietary compensation, 10-15% by fecal loss and another 10% via increased energy expenditure. Nuts are a rich source of various nutrients and despite their high energy they are almost never associated with weight loss when portions don’t go beyond limits. Nuts are excellent choices to include in your diets as they increase palatability, nutrient quality and reduce chronic disease risk while paving way for weight loss as well.

References
Walnut consumption in a weight reduction intervention: Effects on body weight, biological measures, blood pressure and satiety: https://nutritionj.biomedcentral.com/articles/10.1186/s12937-017-0304-z

Impact of providing walnut samples in a lifestyle intervention for weight loss: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5510231/
​
Effect of walnut consumptions on blood lipids & cardiovascular risk factors: https://academic.oup.com/ajcn/article-abstract/108/1/174/5042152?redirectedFrom=fulltext

Nuts and healthy body weight maintenance mechanisms: 
http://apjcn.nhri.org.tw/server/APJCN/19/1/137.pdf