Dr Michael Mosley has warned that snacking at the wrong time of day could spell a serious risk to your health.

The health guru’s BBC podcast Just One Thing revealed that a third of people had snacks after 9 pm. Worryingly, even healthy options after this time could be bad for you.

Dr Mosley said: “One thing that really interests me about snacking is it’s not just what you eat, but when you eat that’s important.”

The subject has been investigated by Doctor Sarah Berry, from the Department of Nutritional Sciences at King’s College, London and chief scientist at health app Zoe. She explained that snacking counts for a huge amount of what we eat.

Dr Berry said: “We are a nation of snackers. 95 percent of people report that they snack. So anything that’s eaten between breakfast, lunch and dinner, or even after dinner, we consider to be a snack, and what we know is that nearly a quarter of our calories per day come from snacks in the UK.”

She highlighted a survey of 1,000 people that focused on the issue of snacking – specifically when people ate, what they ate and how often they snacked.

Dr Berry said: “What we found was that it’s all about the quality and the timing of the snacks. People that were snacking on unhealthy food had higher bad cholesterol, lower good cholesterol. They tended to also have higher weight around the waist.

“Interestingly, we also found that the time of day mattered. A shocking 30 percent of people were snacking after nine o’clock in the evening, even if it was on healthy snacks. You had a higher risk of cardiovascular disease. You had a higher baseline level of blood glucose. You had poorer insulin sensitivity, and you had worse blood fat as well.”

Dr Mosley explained that over the last 40 years, Britons have become “snackaholics”. He said: “We often have snacks on the go, and grabbing a cereal bar or packet of crisps is, of course, incredibly easy and often incredibly unhealthy.

“Three quarters of the snacks we consume here in the UK are heavily processed and high in refined carbohydrates, salt, fat and sugar.

“Not surprisingly, studies have shown that people who regularly snack on starchy foods like crisps tend to be heavier and die younger. But the good news is you don’t have to give them up entirely.

“Cutting back on processed, starchy, sugary snacks and switching to healthier alternatives comes with a multitude of health benefits, including a lower risk of heart disease and switching your snacks could also boost your mental health.”

One study of over 800 Britons found that people who ate processed snacks like crisps most days were far more likely to report symptoms of anxiety, stress and depression compared to those who didn’t.

“By contrast, those who snacked on fruit were less likely to be depressed and more likely to report being in a good mood,” the doctor added.