Is fat really bad for you? Should we consume less salt? And what’s wrong with gluten, anyway? A science writer and a consultant cardiologist separate fact from fiction.
The great diet food con
Have you ever wondered why people on diets seem to be on and off them forever? Or why it’s really only people who struggle with their weight who have extra low-fat mayonnaise in their fridge? Most processed foods branded as diet, low-fat, light or lighter aren’t what they’re cracked up to be. And if you look at their lengthy ingredients lists, you’ll realise that they’re not even very good for you.
Take low-fat mayonnaise. When you strip out the fat you have to reinject flavour with sweetness. So an emulsion of eggs and oil becomes an emulsion of water, maize starch, extra sugar and glucose syrup. Or to put another way: water, sugar, sugar and sugar. That’s an awful lot of sugar, and because the traffic lights on packets of food don’t flash red until a whopping 27g of sugar is in each 100g portion – that’s just under seven teaspoons – a busy shopper won’t think twice about choosing this “healthy” option.
Other culprits are microwaveable low-fat meals. The high glycaemic index, carbohydrates and sugars aside, manufacturers are so busy bending backwards to limbo under the threshold for each of the other traffic-light categories that they often leave out plenty of healthy foods such as positive fats, fruits, vegetables and fibres. It’s why they’re often so tasteless and don’t leave you feeling full for long.
The diet food industry is a headless beast driven by market forces: it makes good business sense to make low-quality food with effective branding. The only way we can bring it to its knees and stop this tyranny of tiny, tasteless meals is to become savvy consumers and stop buying them. If you feel yourself being seduced by an alluringly presented diet food and don’t have time to interrogate its ingredients, a good rule of thumb is to just say no.
Are calories important?
We love to ascribe value to things. It helps us make decisions about a jumble of information, like the way we use calories to help us manage what we eat.
The concept entered public consciousness during the first world war when the state used it to make sure people didn’t overeat during food scarcity. The calorie – the unit of energy needed to heat one cm3 of water by 1C – has since become the backbone of our understanding of healthy eating, but at what cost?
In a perfect world it makes perfect sense. If you consume more energy than your body needs, then according to the central tenet of Einstein’s most famous equation it’ll be turned into mass – a wibbly-wobbly type of mass around your belly and thighs.
The problem is that our bodies don’t burn energy with the consistency of a Bunsen burner. “We do not absorb all the nutrients from some foods,” says Pete Wilde, a professor at the Institute of Food Research in Norwich. “By chewing and eating whole almonds, for instance, we absorb only around two-thirds of the energy listed on the label. The calcium in milk and dairy products reacts with fatty acids and again reduces the energy absorbed.”
The different rates of digestion of different foods can also affect your appetite and determine how much you end up eating. “The more slowly our food is digested the less hungry we’ll feel for longer,” Wilde adds. “The calories absorbed by two different foods could be the same, but if one food is digested more slowly, it’ll make us less hungry and less likely to snack.”
In how your body uses – and stores – energy, 140 calories of cola is not the same as 140 calories of broccoli. If you want to lose weight by starving yourself, then a calorie-restricted diet is the way to go. Though you’ll likely bounce back once you start to eat normally. If you’re after a sustainable way to be healthy it’s best to think a little more about the constituents of your food.
A healthy diet is not about restriction but inclusion of diverse and protective foods. Choosing food on the basis of only calorie content is like choosing your life partner on how quickly they can run 100 metres: it might be useful in extreme circumstances, but for your day-to-day life and general wellbeing, it’s pretty much useless.
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