Long day at work? Let's order in. Not feeling happy? How about a cheat meal! And so on - nowadays, the concept of cooking for oneself seems to have become outdated. But little do we realise that these ordering-in habits can cost you a great deal later - it turns out these can speed up ageing. And it does not end here; eating takeaway food regularly can take away months of your life, and even undo all the health benefits of regular exercise. Researchers at the Peking University Third Hospital in China studied 43,000 adults in the UK to come to this conclusion.How does eating takeaway food affect health?Researchers conducted blood tests on people who regularly eat takeaway food. They found that their biological age was about three months ahead compared to people who ate home-cooked food. This means that their kidney, liver and immune systems were getting worse at a faster rate than usual. Researchers said that treating yourself to junk food every day could undo the benefits of regular workouts, too. Over the years, these effects could knock off months from your life.The study, which was published in the BMC Medicine journal, also noted that the three-month difference in biological ageing, driven by dietary habits, might appear insignificant, but it translates to about a 2.2 to 2.7 per cent increase in early death risk. Over time, this can account for 16 per cent of the severe ageing caused by smoking. Some of the effects, as per experts, were linked to obesity and weight gain. However, people's health was worse even if they were not fat. Some of the effects were because of the weight gain and obesity link, but in the case of some participants, the effects were worse, even when they were not fat.Why is takeaway food discouraged?The study shows that takeaway food is harmful because of its high fat, salt, sugar and calorie content. But more importantly, it is about the absence of nutrients like fibre and protein. These foods are more likely to be eaten quickly and alone, without paying much attention to the poor quality of ingredients used. To make matters worse, plastic packaging contains harmful chemicals like PFAS - upon heating, these can release cancer-causing components. Researchers said that these factors could be associated with inflammation in blood vessels, a dip in levels of healthy gut bacteria, and a heightened risk of heart disease or type-2 diabetes.Experts noted that the effects in terms of accelerated ageing and regular consumption of junk food can cancel the benefits of even regular workouts.