There’s no shortage of diets that either promise to kick start a new healthy lifestyle or are described as the best long-term route to weight loss. But what about those individual foods we see that are said to actually help weight loss? Is there any basis for these claims, or are they just hype? Today we’re going to look at some of these foods and try to explain the scientific basis, if any, behind the claims.
First up, we have peanut butter. Something that contains almost 600 calories per 100g (3.5oz) – equating to around 200 calories per serving – can’t possibly be a diet food, can it? But that same serving also contains 2g of fibre and 8g protein per serving, so it fills you up and keeps you feeling full for longer. It’s also packed with nutrients including magnesium, potassium, vitamins B3, B6, B9 and E and manganese. But the interesting thing about peanut butter is that it’s full of mono-unsaturated fats, meaning this is one food that you shouldn’t buy in the reduced fat form. This is because consuming a moderate amount of these ‘healthy’ fats helps reduce belly fat.
The other great thing about peanut butter is that it has a low glycaemic index, meaning it is digested more slowly and the sugar is released gradually into the bloodstream. So you’ve got vitamins, minerals, protein and fibre, plus healthy fats and the knowledge that you’re getting a long-lasting energy boost and a reduction in sugar cravings rather than just a quick fix. Unfortunately, my favourite Reeses peanut butter cups definitely don’t count as a diet food, even if they do contain peanut butter!
Next up we have apples, which although they contain fruit sugars are much more believable as foods for weight loss. 100g of apple contains under 50 calories and plenty of vitamin C and fibre, but they have another secret ingredient – pectin. This is a chemical found in the cell walls of plants, but particularly apples. You may have heard of pectin as the ingredient added to jams and jellies to help them set, which may give you a clue as to why it’s good for weight loss. When eaten, pectin binds to cholesterol and also traps carbohydrates, which slows glucose absorption within the body. This effectively limits the amount of fat your cells can absorb, so it seems that apples definitely fit the ‘weight-loss foods’ category.So how about blueberries? They’re often classed as a superfood, and they certainly contain high levels of antioxidants, vitamin K and fibre whilst being low in calories. But what of claims that blueberries’ vitamin C content makes them a weight-loss food? Well, I’m afraid I haven’t found anything to back this claim up – although there is a “blueberry diet” which simply says eat 2-3 cups of blueberries a day (together with whatever else you feel like!). While vitamin C levels seem to be related to body weight, and a review published in 2005 in the “Journal of the American College of Nutrition.” claims that people who are deficient in vitamin C may have a harder time losing fat mass, there are plenty of other foods that contain vitamin C and anthocyanins, the antioxidant found in blue and purple foods. However, they do reduce the production of a cholesterol-making enzyme in the liver, so they certainly deserve their superfood tag!