4 weight-loss diet tips that are actually backed by science

  • Marie Claire is supported by its audience. When you purchase through links on our site, we may earn commission on some of the items you choose to buy.
  • Because Dr Stuart Farrimond knows exactly what he's talking about when it comes to maintaining a healthy body and mind

    The diet and weight loss industry is full of headspinning myths and red flags. The number of times I’ve heard of people being advised wrongly or following crazy things, most of which have no evidence behind them, is astounding. However, over the years, scientists have found a number of strategies you should keep in mind that are effective when following an science-based health regime. If you’re struggling with maintaining a healthy body and lifestyle through Lockdown 3.0, you’re not alone. Keep in mind these four essential weight-loss diet tips and be kind to yourself…

    1. Blame the Belgians for BMI baloney

    Ask a doctor or personal trainer about diet tips and your ideal weight, and they’ll probably point you to your BMI (Body Mass Index). It is calculated as your weight in kilograms divided by the square of your height in metres. If your number comes out between 18.5 and 24.9 you’re said to be ‘healthy’, anything above or below puts you over or underweight. Like a hallowed scripture, few people question the BMI scale and its weight categories.

    The science bit: In reality, the formula is a 200-year-old maths hack, based on the sizes and weights of sedentary Belgians. BMI is badly in need of an update. Your BMI score can used as a rough and ready way of guesstimating whether you are significantly over or underweight but anything else needs to be taken with a bucket of salt. BMI doesn’t take account of muscle, which is heavier than fat, and neither does it adjust for height properly.

    Get this: if you’re tall, your BMI will be over-inflated; if you’re shorter than average, your BMI will be unduly low. You can easily be outside the recommended range and be perfectly healthy. It is far better to have your body fat measured, which can be done fairly accurately at home with some decent ‘smart scales’. Failing that, a better a newer, more accurate formula to calculate body fat than BMI is relative fat mass (RFM) – all you need is a tape measure – and there are plenty of online calculators to crunch the numbers for you.

    2. Not all bodies are created equal

    Might the slender-framed among us have a faster metabolism or be born with skinny genes? The truth is that we’re terrible at judging how much we’ve eaten, most of us significantly underestimating the number of calories we eat in a given day – even when we keep a food diary. Sugary drinks, milky coffees, that mid-morning biscuit, and the evening glass of wine are easily (and conveniently) forgotten, but they all add up.

    The science bit: That said, we aren’t given bodies that put us on a level playing field. As far as diet tips go, you have your own unique basal metabolic rate – the amount of energy your body burns just to keep you alive. Generally, the younger and more muscular you are, the more calories you burn. Two identically proportioned people will have different metabolic rates, although it rarely varies by more than about 200 calories per day. Achieving this balance between food intake and your personal metabolic rate can be a constant challenge. On average, everyone gains about 0.5kg every year, but we can’t blame a falling metabolism: our weight creeps up mostly because we exercise less as we get older.

    3. Is my weight genetically programmed?

    Your genes decide whether you will be tall, short or a born marathon runner. And at least 50 of your genes determine how good you are at accumulating a padding of fat.

    The science bit: For instance, if you have an abnormal version of a gene called MMP2, your body can create body fat quicker than most. Around a third of women have this fat-building gene. Such people are blessed when faced with famine but cursed in our world of cheap, fast food. Another gene, FTO, sets the gauge on how much pleasure you get from eating by determining how much of the hormone dopamine is released when you eat. People who carry a particular version of this gene are 20-30% more likely to be obese, and will be on average about 1.5kg heavier than non-carriers. You are not powerless though – research shows that regular exercise can negate the effects of a faulty FTO.

    4. Which is the best weight-loss diet?

    As far as diet tips go, losing excess weight is simple – if you put less fuel into your body than it needs, it will burn its excess fat. But the reality is incredibly difficult for many of us. There is no perfect way to shed excess fat, although there are plenty of very bad ways. Beware of diet-speak mumbojumbo: ‘Clean’ and ‘natural’ don’t have any proper definition and simply hark to vague mythical ideas of a ‘purer’ past.

    The science bit: Theories about ‘detoxing’ and balancing levels of acid and alkali are pure make-believe, based on zero science. Some diets will shed pounds, but not for the reasons you might think. Cutting out carbohydrates works because foods high in protein are more filling than starchy foods. It’s much easier it is to scoff a medium portion of carb-rich chips than it is to polish off two chicken breast fillets (a high protein food with almost no carbohydrate), even though both contain the same amount of energy. Unless under strict instruction from a doctor, always avoid rapid weight-loss programmes, 10% of the weight you lose on a crash diet is muscle, not fat. Mental health usually takes a hit, and risks of obsessive thinking are high.

    * The Science of Living by Dr Stuart Farrimond (published by DK) is out now

    Reading now