Nuts may provide up to 26 per cent less kilojoules than previously thought. A series of studies, from the US…
Nuts and their fats
Nuts and their fats
The fat in nuts is mainly the healthy (unsaturated) type, which is crucial for heart health.
Healthy mono- and poly-unsaturated fats – found in nuts, and other foods like seeds, avocado, olives and fish – can help improve cholesterol levels by decreasing ‘bad’ (LDL) cholesterol and increasing ‘good’ (HDL) cholesterol (1). In turn, this can help lower heart disease risk. Eating too much saturated fat, on the other hand, can increase the risk of heart disease.
The type of fat you eat is more important than the total amount. Heart Foundation (1)
The types of fat in nuts
With the exception of chestnuts (which are very low in fat), nuts contain around 50-75 per cent fat (2).
Nuts contain mainly the healthy or ‘good’ mono- and poly-unsaturated (omega-3 and omega-6) fats, with a much lower proportion of the ‘bad’ saturated fats (<15% total fat).
The fat profile of each nut varies. For example:
- Almonds, cashews, hazelnuts, macadamias, peanuts, pecans and pistachios are higher in monounsaturated fats
- Brazil nuts, pine nuts and walnuts have more polyunsaturated fats.
- Walnuts are one of the few plant foods that contain alpha-linoleic acid (ALA) omega-3 fat, with smaller amounts found in pecans, hazelnuts and macadamias.
Table 1: The fat content of nuts per 100g
|Nut type||Total fat (g)||Saturated fat (g)|| Mono-|
unsaturated fat (g)
unsaturated fat (g)
|Omega 3 ALA (mg)||Omega 6 LA (mg)|
Figures from Food Standards Australia New Zealand (2022). Australian Food Composition Database – Release 2. Canberra: FSANZ. ALA = alpha-linoleic acids; LA = linoleic acid.
Graph 1: The fat profile of nuts
SFA = Saturated fatty acids; MUFA = Monounsaturated fatty acids; PUFA = Polyunsaturated fatty acids; n3 = omega 3 PUFA; n6 = omega 6 PUFA.
Did you know? Not all the fat in nuts is absorbed. Instead, nut eaters excrete some of this dietary fat (around 5-15%) in their stools.
Omega-3 fatty acids
Omega-3 fats can be divided into short chain (from plants) and long chain (mainly in seafood). Alpha-linolenic acid (ALA) is an essential short chain omega-3 fatty acid – meaning it cannot be made in the body, so must be obtained from our diet. Intake of heart-healthy ALA has been linked with a lower risk of dying from all causes. Walnuts are one of the few plant foods rich in omega-3 ALA.
Omega-6 fatty acids
Omega-6 is another type (or ‘family’) of polyunsaturated fatty acids. Linoleic acid (LA) is the most common form of omega-6 fatty acids. As with omega-3s, our body can’t make omega-6s, so we must get them from our diet. Omega-6s are found naturally in whole plant foods, including nuts (and walnuts, pine nuts and Brazil nuts contain the most).
Health authorities recommend we balance our intake of omega-6s and omega-3s, with an ideal ratio in our total diet of 1:1. Nutritious, plant-food sources of both ‘omegas’ (like nuts) are healthy options. Highly-processed ‘discretionary’ foods rich in omega-6 fatty acids – such as cakes, biscuits, burgers, pizza and chips, which contain large amounts of processed seed and vegetable oils – should be limited.
Omega-7 fatty acids: An emerging fatty acid
Omega-7 fats are found in certain fish and nuts, like macadamias, and are also produced by the body. A common type of omega-7 fatty acid is palmitoleic acid – which is thought to counteract palmitic acid (a saturated fatty acid that raises ‘bad’ (LDL) cholesterol, and has been linked with an increased risk of cardiovascular disease).
Did you know? Despite their high fat content, nuts are not associated with weight gain. In fact, research suggests the opposite (3-5). More than 20 years of scientific research shows nut intake is linked with a reduced risk of overweight and obesity, and a reduced body weight, body mass index and waist circumference.
The bottom line
The type of fat you eat is more important than the total amount. And for heart-health benefits, unsaturated fats win hands down. Aim to include a handful (30g) of nuts in your day, each day, as part of a balanced diet, for a healthy dose of mono- and poly-unsaturated fats!
- Heart Foundation. Fats, oils and heart health. Accessed 14 June 2022. Available at: https://www.heartfoundation.org.au/heart-health-education/fats-oils-and-heart-health
- Food Standards Australia New Zealand (2022). Australian Food Composition Database – Release 2. Canberra: FSANZ. Accessed 14 June 2022. Available at: https://www.foodstandards.gov.au/science/monitoringnutrients/afcd/Pages/default.aspx
- Eslami O, Shidfar F, Dehnad A. Inverse association of long-term nut consumption with weight gain and risk of overweight/obesity: A systematic review. Nutr Res, 2019. 68:1–8.
- Flores-Mateo G, et al. Nut intake and adiposity: Meta-analysis of clinical trials. Am J Clin Nutr, 2013. 97:1346–55.
- Guarneiri LL., Cooper JA. Intake of nuts or nut products does not lead to weight gain, independent of dietary substitution instructions: A systematic review and meta-analysis of randomized trials. Adv Nutr, 2020
Published June 15, 2022