The 10,000 steps myth and other health targets debunked
The 10,000 steps a day idea has become one of the popular health mantras of the past decade, with the emergence of Fitbits and other wearables all fuelling a step counting obsession.
However while the World Health Organisation, the American Heart Association and many others have all adopted the 10,000 steps a day goal, the number is actually completely arbitrary, originating in a Japanese boardroom in the 1960s. Few people realise but the company Yamasa simply dreamt up the figure as a way of promoting the world’s first step counter ahead of the Tokyo 1964 Olympics.
Instead actual research has suggested that between 6,000 and 8,000 steps per day might be the sweet spot for avoiding chronic illness. A new study published by scientists at the University of Alabama at Birmingham School of Public Health has found that if you currently live a fairly sedentary life, even just adding an extra 500 steps a day will bring significant health benefits.
“People obsess over how many steps are enough but we should be asking how many steps are too few,” says Catrine Tudor-Locke, a professor and physical activity researcher at the University of North Carolina at Charlotte, who has studied the 10,000 steps a day phenomenon. “We should get people to stop taking less than 5,000 steps a day, but there seems to be an obsession with the higher number, while it’s more important from a public health point of view to just get people off the couch and out the door.”
10,000 steps a day is just one of many public health doctrines that are grounded more in myth than actual science. Here are some others:
Five a day
Perhaps the best known piece of public health advice of all time, first conceived by the UK government in the late 1980s with the aim of encouraging people to eat more dietary fibre – the plant based carbohydrates found in fruit, vegetables, cereals, nuts and seeds.
But in fact, studies have shown that five a day is unlikely to be enough to give us full protection against various chronic illnesses. One study from nutritionists at Imperial College London found that in reality we would probably need to eat seven or even ten a day to provide our body with all the nutrients and fibre we need.
Charlotte Evans, a researcher in nutrition and public health at the University of Leeds, says there needs to be a push for people to make fibre the majority of their daily diets, rather than processed foods. “When the dietary recommendations were originally set, it was designed as the optimal to prevent weight gain in the first place,” she says. “But now we’re in a situation where two thirds of the population are already overweight.”
Eight hours sleep
The idea that everyone needs eight hours of sleep per night goes back to Victorian England. At the time of the industrial revolution, a daily regime of eight hours labour, eight hours recreation and eight hours rest was commonly prescribed.
But we now know that the amount of sleep we require is highly individualised, and is dictated by a complex mix of genetics, age, medical conditions and lifestyle. Some people can function perfectly well on less than six hours, while others need more than ten hours to feel at their best.
According to Russell Foster, professor of circadian neuroscience at the University of Oxford, individual sleep patterns are akin to shoe size. “I think that the myth of the eight hours has actually caused quite a bit of anxiety,” he says. “There’s actually a huge amount of variation.”
Two litres of water a day
Two litres of water per day, or approximately eight glasses, has been standard advice for decades but our fluid requirements actually vary a lot depending on how much exercise we do, the weather, climate, and age.
Depending on circumstances, people may need as many as six litres, if they are working out a lot in hot weather, or as little as one. Various online hydration calculators attempt to give you an idea of what your daily water intake should be, based on a short questionnaire.
According to Dale Schoeller, emeritus professor of nutritional sciences at the University of Wisconsin-Madison, the science has never supported the two litres a day rule as an appropriate guideline. “A lot of your water comes from the food you eat,” he says.
Breakfast is the most important meal of the day
Our modern day obsession with breakfast goes back to the 1920s, when early marketing campaigns from cereal companies placed a big emphasis on the supposed healthiness of breakfast. As people became more and more preoccupied with the concept of vitamins, savvy cereal brands began touting the nutrient content of their products, while in recent decades claims have even been made that breakfast might help you lose weight.
But whether breakfast is even necessary remains up for scientific debate, while nutrition experts say that its health benefits depend on what you are actually eating. A breakfast consisting of highly processed foods and a large sugar content is likely to do more harm than good.
“The evidence that eating breakfast helps you lose weight largely comes from studies where there’s a suspicion that those people might be eating more healthily in general,” says Kevin Murphy, a professor who researches metabolism and digestion at Imperial College London. “Other studies have suggested that in trials where you are asking people to change whether they eat breakfast or not, in fact breakfast is likely to drive people to eat more calories during the day.”
2,000 calories a day
According to the NHS, the recommended daily calorie intake is 2,000 calories a day for women and 2,500 for men.
But just like with sleep and water intake, our calorie needs depend on many things for example, age, gender, height, weight and physical activity levels. Some people will need to reduce or increase their calorie intake in order to maintain a moderate weight.
Many dietary experts are questioning the relevance of the calorie fixation in our diets because not all calories are created equal.
As Giles Yeo, professor of molecular neuroendocrinology at the University of Cambridge pointed out in his 2021 book Why Calories Don’t Count, the body absorbs the calories present in various foods very differently.
“Calories don’t take into account the energy it takes our cells to metabolise food in order to use it,” he says. “A calorie of protein makes you feel fuller than a calorie of fat, because protein is more complex to metabolise. You could be aiming to eat 2,000 calories a day, but how much energy your body actually absorbs will depend on whether you’re eating sugar, celery, or steak.”