Dr Michael Mosley says cutting this one food out of your diet can slash risk of heart disease and cancer

Dr Michael Mosley says cutting one type of food out of your diet can radically cut the chances of having heart disease, cancer, and type 2 diabetes. Speaking on his BBC podcast Just One Thing, the well-known TV doctor explained how people could also boost their mental health, trim a few inches from their waistline and even save a few quid too with this one tip.

Dr Mosley was talking about the benefits of cooking from scratch and cutting ultra-processed foods out of our diets. The NHS website says that processed food is something which 'has been altered in some way during preparation'. It adds: "Ingredients such as salt, sugar and fat are sometimes added to processed foods to make their flavour more appealing and to extend their shelf life, or in some cases to contribute to the food's structure."

Cooking from scratch, on the other hand, is 'making real food with real ingredients, whether fresh, frozen or dried', Dr Mosley says. He claims that home cooking can reduce calories and increase mental health, and help your gut microbiome too.

The UK is one of the worst offenders in Europe when it comes to ultra-processed foods. Estimates vary, but some say as many as two thirds of the calories the nation consumes are from ultra-processed foods.

"Despite watching more cooking shows than ever, we eat worse than ever," Dr Mosley said. "Two thirds of our calories from ultra processed food – foods typically made in factories with five or more ingredients like sweeteners and emulsifiers that you don’t normally use in home cooking.

"They can be a quick and easy option but they are often an unhealthy one. An umbrella review published in the BMJ found a clear link between a diet high in ultra-processed food and 32 harmful health effects, including higher risks of heart disease, cancer, type 2 diabetes, poor mental heath and early death.

"But the good news is cooking from scratch more frequently can have a big positive impact – particularly on your waistline. A study of more than 11,000 people found that those who ate home-cooked meals more than five times a week were 28 per cent less likely to be overweight than those who cooked from scratch three times a week or less.

"Not only were their meals healthier, but researches say home cooking also improved their eating behaviour. They snacked less, had smaller portions and more shared meal times.

"And getting creative in the kitchen can also boost your mental health. Studies in both healthy volunteers and cancer patients have found learning to cook has a big impact on well-being. This could be because when cooking from scratch, you tend to make healthier food choices. Simply learning a new skill will boost confidence, which elevates self-esteem."

That view was backed by Dr Emily Leeming, a nutrition scientist from King's College London. She said: "Ultra-processed foods are made and engineered to taste delicious, and we know that the things that make foods taste good are higher sugars and higher fat. Those aren’t bad things in themselves, but they do tend to make us go over our energy needs, and that is a problem.

"Sixty per cent of our diets in the UK come from ultra-processed foods, and that displaces foods that our gut bacteria really enjoy. That is foods that are full of fibre – that plant roughage in fruit, vegetables, whole grains, beans and legumes. That then starves our gut bacteria from being able to do all those beneficial things that we know they do for our bodies."

She said that people tend to eat more fruit and veg when they cook from scratch - and there are studies to back this up. One, in the US, had people eating either ultra-processed or whole, homecooked foods for four weeks.

The group on ultra-processed foods consumed an average of 500 calories per day more than the other group. They also gained an average of 1kg in weight, while the whole food group on average lost 1kg. Whole foods tend to have less salt, which usually means lower blood pressure and a lower risk of heart disease.

Dr Leeming said that 70 per cent of salt people consume is not the stuff that we add to our food from a container, but 'invisible' salt already in the foods that we are cooking with and eating.

Her top tip was to keep your freezer full of frozen fruit and veg. She said that, in this day and age, food is often frozen very quickly after being picked, meaning it retains many of its nutrients.