When it comes to weight loss, common advice is to swap out unhealthy snacks like chocolate and crisps for healthier alternatives like nuts and seeds. However, despite their health benefits, are nuts helping or hindering your weight loss?
Nuts are nutrient dense, and depending on the nut, can be high in vitamin E, C, calcium, magnesium, omega 3, zinc and potassium. See the following link for a comprehensive overview of the vitamins and minerals in various nuts and seeds http://www.health-alternatives.com/nut-seed-nutrition-chart.html (1)
WHAT ABOUT PROTEIN?:
Increased protein intake while trying to lose weight is advised (2) especially alongside resistance training. This is firstly because, protein is more satiating (filling) than carbohydrates or fat, and also supports the maintenance of lean muscle tissue while in a calorie deficit (3).
Nuts are often promoted as a great source of protein by health magazines and blogs, but this simply isn't the case. The usual recommended serving size for nuts is 30g. 30g of almonds are around 200kcal and provide only 6.5g of protein. This is similar ratios to boiled potatoes which contain 6g protein per 220kcal.
The problem is, nuts are extremely calorie dense, to get 20g of protein from almonds (a decent protein serving) you would need to consume around 600kcal in the process. When compared with chicken breasts, that provide 48g of protein per 200kcal, sourcing your protein from nuts is extremely inefficient.
NUTS ARE ENERGY DENSE: BE CAREFUL WITH PORTION SIZE!
28g of macadamia nuts, is about 10 nuts(!) and packs the same calories as a Mars bar. While macadamias are packed full of vitamins, and high in omega 3s - this isn’t going to affect your weight loss efforts if you're eating too many calories!
The dangerous thing about nuts, is the perception that 'healthy eating' = weight loss. Most people trying to lose weight probably wouldn’t sit at their desk eating Mars bar after Mars bar. However, in the name of ‘good health’ it is more than feasible to get through a hand-sized 100g bag of macadamias in an afternoon (that's just 40 nuts). This is 752kcal, the equivalent of two meals, and as many calories as a large margarita pizza.
NUTS FOR WEIGHT LOSS: ARE THERE BETTER OPTIONS?
Nuts are certainly a healthy snack option, and I would always recommend 30g of cashews over a Mars bar! However, remember when it comes to weight loss, energy balance is king, meaning calorie intake and expenditure is of upmost importance! (4)
If you’re looking for a truly filling, nutritious, omega 3 packed, high protein snack for the same calories as a handful of nuts - why not try this instead:
Smoked salmon with lemon (100g), low fat cottage cheese (150g) and a side of kale (100g)
310kcal, 40g protein! Done!
[BONUS NOTE ON GOOD vs. BAD FATS:]
A commonly held belief about food such as nuts, avocado and olive oil, is that their high fat content comes from ‘good' (unsaturated) fat that should replace ‘bad’ (saturated) fat to lower the risk of heart conditions.
However, while there are studies to support this (5) (6), large scale meta-analysis from 2014 found that: ‘Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.’ Chowdhury R, et al (2014) (7)
Also, further meta-analysis from 2015 found ‘No association between dietary intake of saturated fatty acids and incident coronary events or mortality in patients with established Cronary Artery Disease.’ Puaschitz NG, et al (2015) (8)
These reviews cast doubt on the legitimacy of traditional notions of ‘good’ (unsaturated) and ‘bad’ (saturated) fats and their role in heart health. Obesity however, is widely accepted to increase risk of heart disease (9). So if the goal is lowering your risk of heart disease, then obtaining normal levels of body fat should be a higher priority than increasing 'good' fat intake.
The dense micronutrient profile of nuts and seeds make them a positive inclusion in a balanced diet. However for weight loss or reducing obesity for cardiac health, make sure the portion size is as suggested, and/or fits within a sensible calorie target.
(2) https://www.ncbi.nlm.nih.gov/pubmed/25926512 Leidy, HJ et al (2015)
(3) http://onlinelibrary.wiley.com/doi/10.1002/oby.20078/full tang M et al (2013)
(4) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3401553/ James O. Hill, Ph.D (2012)
(5) https://www.ncbi.nlm.nih.gov/pubmed/26068959 Hooper L et al (2015)
(6) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257681/ Emillio, R. et al (2010)
(7) http://annals.org/article.aspx?articleid=1846638#tab10Div Chowdhury R, et al (2014)
(8) https://www.ncbi.nlm.nih.gov/pubmed/25644351 Puaschitz NG1 et al (2015)
(9) https://www.ncbi.nlm.nih.gov/pubmed/21855700 Zalesin KC, et al (2011)