If you are trying to lose weight, or indeed avoid gaining it, you might take a cursory glance at the nutritional info on a pack of nuts and dismiss them as too high in calories to be a smart snacking choice.
This would be a mistake. Nuts are high in calories, but there are several reasons why that shouldn’t exclude them from your snacking repertoire. New research from Harvard University tracked the eating habits of 300,000 people over 30 years and found that those who ate half a portion of nuts each day gained less weight and were less likely to become obese.
To discuss the study and get more info on what makes nuts a healthy snack option, we spoke to dietitian Juliette Kellow, who is working as an independent consultant dietitian for the Almond Board of California.
If nuts are high in calories, how do they help you avoid weight gain?
There’s probably lots of different reasons for this. One of the first things to say is that it’s very difficult to look at one individual food and come up with a great big conclusion on the impact it has on our health. We don’t eat just nuts – they’re part of a much bigger diet. It may well be that in the studies that have shown better weight control in people who consume higher amounts of nuts, their diets are better overall: they’re eating more fruit and veg, and not as much high-calorie food like crisps, biscuits and cakes.
But we also know that nuts contain protein and fibre, both of which have been shown to be important in improving satiety – that feeling of fullness after you’ve eaten. It may well be that nuts help to curb hunger. We’ve seen in studies that a 42g serving of almonds as a snack helps to reduce the overall calories that are eaten at lunchtime and dinnertime, compared to no snack at all. So you might have more calories in mid-morning, but you’re compensating because you feel fuller and not as hungry by having fewer calories at lunch.
Then there’s the crunch factor. We know that eating crunchy foods means that the food stays in our mouths for longer because we’ve got to chew it. The chewing action and the fact your food is in your mouth for longer is more likely to trigger responses in the body that send messages to the brain to help us recognise we’re full.
Finally, we’ve seen research that perhaps we don’t get all the calories from nuts that we expect to. Because they are a hard, crunchy food, it’s difficult for the body to break the cell wall down, so it may well be that some of the fat isn’t absorbed as effectively as it would be with a soft food. We’ve got studies showing you get roughly 25% fewer calories from that portion of nuts than you’d expect to when looking at the label, simply because some of that fat isn’t being absorbed but is passing into the large intestine undigested. Obviously that’s not great if you’re in a situation where you’re starving! But in a well-nourished population, that could be a benefit.
What makes nuts healthier than other common snacks?
Nuts are a nutrient-rich snack. This is one thing that often gets lost when we talk about healthy eating – we have to look at what else is coming with your calories. If you focus just on calories alone, you’re not looking at the overall picture. There’s a big difference between getting 200 calories from a food that contains fat or processed carbs and not much else and getting 200 calories from a portion of nuts.
Almonds are high in fibre, they’re a source of protein, they contain good fats – the unsaturated kind, which have been linked with better heart health – and you also get this vast array of vitamins and minerals. They’re high in calcium, magnesium, phosphorus, potassium, zinc, copper, manganese. They’re a source of iron, thiamine, niacin and folate. And they’re very high in vitamin E. It’s probably easier to list what they don’t contain! It’s a similar pattern for most nuts, though they’ll all vary in what they contain.
What counts as a portion of nuts?
We normally say a handful of nuts, which is difficult because people have different-sized hands! It’s about two tablespoons, or 28-30g. A portion of almonds would be 23 almonds, but if you work on roughly two tablespoons or a smallish handful, that’s a good guideline.
Can you eat nuts every day, or should they be an occasional addition to your diet?
It’s about looking at what else is going on in your diet. If you have somebody who was maintaining their weight and they suddenly added a handful of nuts to their diet every single day and didn’t make any other changes, they probably would notice they’re starting to put on weight.
However, if they’re taking something else out, like a bag of crisps, or a muffin or a doughnut, and having nuts as a snack instead then that’s beneficial. You’re losing a lot of calories and not many nutrients, and replacing them with probably fewer calories overall and adding in a load of nutrients. It’s a double whammy.
We know from all the research that the people who are the highest consumers of nuts tend to have healthier waistlines and better heart health, so it would seem that there is no reason you couldn’t enjoy a handful of nuts every day. Obviously you want to be getting unsalted ones, and making sure they’re replacing something in your diet that’s less nutritious.
To be clear then, roasted and salted nuts are not the way to go?
You don’t want to replace one salty snack with another salty snack – we’re all eating too much salt! Also, I always recommend portioning out snacks. If you carry around a huge bag of almonds you’ll find you’ve eaten half of it without thinking. Being mindful and putting 23 into a small container means you have your portion there.