Counting calories doesn't work. Try eating smarter instead The time of day you have a meal, how fast you scoff your food and even how much you chew it can affect how many calories you get from it. The time of day you have a meal, how fast you scoff your food and even how much you chew it can affect how many calories you get from it. The key to maintaining a healthy weight, accepted wisdom suggests, is to count the calories we eat against the calories we expend. It makes sense – energy in versus energy out. Sounds simple, doesn't it? But this way of thinking misses an important truth: not all of our food's calories are the same. There's actually a complex biological interaction taking place inside our bodies, influenced by the type of food we eat, how quickly we consume it and its interaction with the bustling community of microbes living inside our guts. "This is a huge expanding area of research," says Sarah Berry, professor of nutrition at King's College London in the UK. "We're really starting to see just how variable our responses are to food – and that I could eat something that I would metabolise in a very different way to how you might metabolise the same food."What we eat clearly still matters – a diet filled with fresh vegetables is going to be better for you than one dominated by cheeseburgers. But it's far from the only consideration. The timing of food, for example, also plays a role in how well we digest it and what nutrients our bodies extract.when they consumed the majority of their calories at breakfast time, compared to those who ate most in the evening, even though they were eating the same total number of calories. Another small study by researchers in the UK found that reducing the amount of time between your first and last meal of the day may lead you to eat fewer calories overall. When healthy but slightly overweight adultsand ate their last meal 90 minutes earlier than normal, their energy intake was lower and they saw a drop in body fat compared to a control group, even though they had access to the same amount of food.It takes time for the gut hormones that regulate our appetite to rise after eating, which is why we can feel a meal hasn't been quite enough at first has been linked to high blood sugar and higher levels of bad cholesterol, which could increase the risk of obesity and cardiovascular diseases.But when we eat isn't the only time-related issue we need to think about when it comes to food. It's worth looking at how fast we eat too.and asked them to either eat it quickly – in five minutes, or savour the taste over 30 minutes. Slower eating increased the release of gut hormones that regulate appetite, including GLP-1, the glucagon-like peptide that modern weight loss drugs such as semaglutide mimic to reduce hunger.of a gut hormone called cholecystokinin – which is responsible for early feelings of satiety – to rise to sufficient levels in our blood stream. It takes 30-60 minutes before GLP-1 and another hormone called peptide tyrosine-tyrosine reach their peak levels and reduce our appetite. These then remain elevated for three to five hours. This explains why some of us might prefer a sweet treat immediately after a meal, but the craving goes away if we wait a while.. In one study participants who ate more slowly also better remembered what they ate and consumed less later on too. Their brains subsequently showed activity in areas related to fullness and reward. By changing the structure of the food, it also changes how quickly the food is metabolised – Sarah Berrywhere individuals ate a meal in 10 minutes on one day and the next day ate the same meal in over 20 minutes. When eating faster, the participants showed increased blood sugar, which over time canWhen we eat food, the number of calories we absorb depends on the structure of the food in front of us, as this can determine Take almonds. A handful consists of about 160-170 calories. How much of these we absorb depends on how we eat them.. If we carefully chew the almonds, chances are we'll absorb all the calories, but if we only partially chew them, we won't, says Berry. Our bodies will also extract, which can lead to weight gain. "By changing the structure of the food, which changes the texture of the food, it also changes how quickly the food is metabolised, where it's metabolised and where the nutrients are absorbed."How much we chew our food and the time we spend eating it can have a significant influence on the total number of calories we consume even when eating the same food, blood glucose levels vary widely between people. Some individuals show greater sugar spikes to tomatoes and some to bananas, for instance. The scientists suggest this may be due to the microbes that live in our guts – our microbiota. The species and balance of microbes in our gut differ from person to person, meaning they also metabolise the food we eat differently. This goes some way towards explaining why some people seem to find it easier to maintain a healthier weight than others.Even identical twins can have different metabolic responses to the same food. In a recent study involving more than 1,000 twins and unrelated adults, there wasbetween twins after eating the same food. Some participants had sharp spikes in blood sugar and insulin, while others showed milder changes.while limiting sugar, salt and fat. 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