I have been encouraging readers to eat nuts as a healthy snack for many years. However, there has recently been a “nut explosion” in the field of nutrition, which has positive spinoffs for health, but appears to impact very negatively on agricultural water supplies.
The prime nut in this controversy is the almond which evidently has so many positive attributes and has become so popular that its ever-expanding production could threaten the future of agriculture in drought-plagued California.
Human beings have known the value of nuts since the time of our hunter-gatherer ancestors when the women of the tribe searched for these valuable foods. More recently, researchers have been investigating the health benefits of nuts in general and almonds in particular.
Read: Almonds on par with fruit/veggies
In 2003 the results of a study designed to compare the effects of an almond-enriched or complex carbohydrate-enriched slimming diet on 65 overweight or obese adults were published. The participants were aged between 27 and 79 with an average BMI of 27-55 kg/m2.
The almond-enriched diet represented a diet rich in monounsaturated (MUFA fats) which are known to have beneficial effects on blood fat levels. The participants who were assigned to the formula-based low-calorie (LCD) almond-enriched diet ate 84g of almonds a day for 24 weeks, while the complex carb-enriched group (CHO-LCD) were allowed to select complex carbohydrate foods instead of the nuts during the study period.
The two groups consumed the same amount of energy and protein during the study, but the almond group obtained 39% of their energy from fat (25% MUFA) and 32% from carbohydrates. The complex-carb diet provided 18% of energy from fat (5% MUFA) and 53% from complex carbohydrates.
The results of this study
The LCD-almond (high MUFA) group compared to the complex-carb group achieved:
- Greater weight loss/BMI reductions (-18% vs. -11%)
- Greater reduction in waist circumference measurements (-14% vs. -9%)
- Greater reduction in fat mass (-30% vs. -20%)
- Greater improvement in systolic blood pressure (-11% vs. 0%)
It is important to note that the complex-carb group had a better average increase in high-density lipoprotein cholesterol (“good HDL cholesterol”), and that improvements in glucose, insulin, diastolic blood pressure, and all the other blood fats showed the same positive improvements for both diets; effects probably thanks to the weight loss the subjects experienced.
Read: Some fats boost good cholesterol
Despite the positive findings achieved with the complex-carbohydrate diet, the greater weight loss produced by eating 84g of almonds a day which boosted MUFA intake, hit the headlines and made almonds a popular diet food.
In June 2015, O'Neil and her team published another study that investigated what effects the inclusion of tree nuts in the diets of a very large number of test subjects, had on health and weight. The NHANES 2005-2010 data collected from more than 14,000 American individuals was analysed to determine these effects.
The NHANES is the National Health and Nutrition Examination Survey which is carried out in the USA annually to track health and nutrition trends. Tree nuts in this study included: almonds, Brazil nuts, cashews, hazelnuts (also called filberts), macadamias, pecans, pine nuts, pistachios and walnuts. Nut consumers were defined as those subjects who ate 1/4 oz = 7 gram or more of tree nuts compared to non-consumers who ate less than 7 grams of tree nuts daily.
This very large study also found that the people who ate tree nuts (7 grams or more per day) had lower BMI values, waist circumference measurements, lower systolic blood pressure, less insulin resistance and higher HDL cholesterol levels than the subjects who ate no tree nuts or only very small amounts. The subjects who ate tree nuts were also 23% less likely to be overweight or obese compared to those subjects who did not eat tree nuts.
Read: Could I be insulin resistant?
These findings have made the popularity of tree nuts, particularly of almonds, soar and most health and slimming sites are encouraging their readers to eat almonds for weight loss, to improve their skin and hair, reduce their insulin and blood sugar levels, reduce neuro-degenerative diseases including Alzheimer’s disease, and respiratory conditions and protect themselves against early death.
Nuts, especially almonds are the “in thing” for general health and weight loss and as an article in the Sunday Times reported this week, “Fatties must be nuts to avoid almonds”.
Using nuts for weight loss
If you are not allergic to nuts of any kind, tree nuts of all types can be used as part of a healthy, balanced slimming diet. They make a nutritious, satiating snack, provided you don’t get hooked on the taste and start nibbling whole packets of nuts in one sitting. Although almonds are indeed nutritious, the fact that the above mentioned investigation studied “tree nuts” and not just almonds, should be kept in mind.
Read: Nut allergy alert
Tree nuts and avocados, olive oil and olives, contain beneficial MUFA fats which raise HDL-cholesterol and lower LDL-cholesterol (“bad” cholesterol). Tree nuts such as pine nuts and pistachios, walnuts and pecans are popular components of many Mediterranean dishes.
High price and High energy
The disadvantages in the short term of eating too many nuts, such as almonds, is that good quality nuts are relatively expensive (nut prices vary from about R15.00 to R37.00 per 100g), depending on where you purchase the nuts, which type of nut and what quantity you buy. In addition nuts are also high in energy because of their high fat content.
The SA Food Tables list the following energy values per 100g for some popular tree nuts:
- Almonds, blanched: 2604 kJ
- Brazil nuts, dried: 2910 kJ
- Hazelnuts, dried: 2797 kJ;
- Macadamia nuts, dried: 3101 kJ
- Mixed nuts (almond, cashew, peanuts [not a tree nut], hazel, Brazil): 2685 kJ
- Pecan nuts, dried: 2943; Pistachio nuts, dried: 2563 kJ
- Walnut, dried: 2944 kJ
Pistachios and Hazel nuts have the lowest energy contents, while Macadamias have the highest energy value. Always remember that the study performed in 2003 also used a low-energy diet which will have contributed to the weight loss results.
So while it is a good idea to use a modest handful of tree nuts (30g) as a snack when slimming, don’t get carried away and sabotage your diet by eating excessive quantities. Also take note that eating candied, sugar-coated or salted nuts is not advisable when you are trying to lose weight or stay healthy!
Almonds and the drought in California
The long-term effects of the unprecedented popularity of almonds is that almond production in California which comprises approximately 80% of the world’s almond crop, has been identified as one of the reasons why the state of California is running out of water. A much quoted statistic is that “cultivating a single thirsty almond takes more than a gallon of water”.
Read: Water shortage
Water restrictions are already being imposed by the authorities in California and legislation is being formulated to control the use of groundwater reserves to prevent underground aquifers from drying up.
According to SADC statistics, South Africa consumes 0.1% of the world’s almond crop, but is not listed as a serious producer. If Californian supplies of almonds are drastically reduced by drought, then slimmers in South Africa may be in for a lean time when it comes to sourcing almonds.
It would appear that eating a modest portion of tree nuts (not just almonds) can promote health and stimulate weight loss when combined with a low-energy diet and physical activity. Slimmers should be careful not to overdo their intake of nuts which have a high energy content and are often a source of excess salt (sodium chloride). If the global almond supply is affected by drought, it is good to know that there are other types of tree nuts, such as pistachios and hazelnuts, which can be used as substitutes.
Eat nuts to stay healthy and lose weight
Go nuts for your health
Adding nuts is a healthy choice
- Dillan J (2013). Using almonds for weight loss, more energy and better skin.
- Indo-Asian News Service (2015). Fatties must be nuts to avoid almonds. Published in the Sunday Times on 5 July 2015.
- O’Neil CE et al (2015). Tree nut consumption is associated with better adiposity measures and cardiovascular and metabolic syndrome health risk factors in US adults: NHANES 2005-2010. Nutrition Journal:14(1):64; SADC Trade (2015). Almonds Trade Information Brief.
- SAVVII (2015). It’s those nuts again. SAVII News & Views. London.
- Walker T (2015). Drought: Almond growers fight back over reports they are causing chronic water shortages. The Independent, Tuesday 5 May 2015.
- Wien MA (2003). Almonds vs complex carbohydrates in a weight reduction progam. International Journal of Obesity, 27:1365-1372.
- Wolmarans P et al (2010). Condensed Food Composition Tables for South Africa. Medical Research Council, Parow Valley, Cape Town.
Image: Fresh almonds from Shutterstock
Dr Ingrid van Heerden is a registered dietician and holds a doctoral degree in Nutrition and Biochemistry. She believes that "we are what we eat" and offers free nutrition and weight loss advice via her DietDoc service on Health24.com. Read more of her articles.