From ready meals and frozen pizzas to flavoured yoghurts — ultra-processed foods are hard to avoid. 

But according to Dr Chris Van Tulleken, BBC presenter, infectious disease doctor and author of the popular book Ultra Processed People, there are easy swaps to be made. 

Not only will they save you from ingesting additional chemicals added to the food, they can also shave off 500 calories from your daily diet. 

Ultra-processed food (UPF) includes snacks, industrially-made bread and other packaged meals that contain ingredients such preservatives, emulsifiers, artificial colours and flavours not typically used when people cook from scratch.

UPFs now make up roughly half of the calories consumed by the average British adult, and two thirds of that eaten by children in the UK, according to recent data. 

Yet, studies have consistently shown eating too much of the processed stuff can increase the risk of heart attacks, strokes, cancer, and type 2 diabetes. 

Now, in a new documentary, Dr Van Tulleken will reveal why UPFs are so hard to resist — and how to easily swap them for something healthier.

Here are the six alternatives he recommends:

Swap pasta sauce jars for a tin of tomatoes

Instead of using a ready-made tomato sauce straight from a jar to mix in with your pasta, you should try making a simple sauce from scratch. 

 Dr Van Tulleken insists it will only take a couple of extra minutes and can be made with two ingredients — a tin of tomatoes and some salt. 

'If you really want to keep things simple, even just a can of tomatoes with a bit of salt will be fine,' he told the BBC.  

However, if you have a bit more time he suggested frying up some garlic and onions before adding the tinned tomatoes, a bit of salt and some vinegar to make it 'better than anything from the shop.'

Some pasta sauce jars are only minimally processed but others, which have a longer shelf life, are extensively processed.

Even though the main ingredients, such as tomatoes, are healthy, sometimes these sauces are packed with additional salt and sugar.

A typical jar of tomato pasta sauce flavoured with garlic and basil is about 300 calories.

But a tin of tomatoes contains just 100 calories, meaning you could be saving 200 calories by making this swap. 

Homemade stir-fry sauces over a packet

Pre-made sauces for a stir-fry are a time-saving option frequently promoted on supermarket shelves, but Dr Van Tulleken offers a recipe idea he claims will take a minute to make — about the same amount of time as it takes to open a packet.

Rather than using a pre-mixed sachet on your noodles, he recommends making a quick sauce with one-third water, two-thirds soy sauce, some sugar, sesame oil and a splash of vinegar.

If you have a bit more time you could also opt to add spices such as star anise, he adds.

Buying a pre-mixed Chinese style stir fry sauce is about 75 calories, but making your own at home is only 50 — saving you approximately 25 calories without the added chemicals. 

Tea and coffee is better than energy drinks

You don't need to give up caffeine when choosing to cut out UPFs, just don't guzzle sugary energy drinks, Dr Van Tulleken warns.

An energy drink contains about 110 calories and about 30g of sugar per 250ml can, while a cup of coffee with a splash of semi-skimmed milk contains about 20 calories — saving you 90 cals. 

Because a coffee is just made of beans and water, even if you add in two spoons of sugar it's much better for you than energy drinks, he claims.

'The one bit of advice I will give anyone is that human beings should only drink water, or if your culture allows it, milk,' Dr Van Tulleken said. 

Some experts suspect drinking too many energy drinks may increase your risk of colon cancer, due to the drinks' high levels of sugar and taurine — an amino acid commonly found in meat, fish and eggs and added to many energy drinks including Red Bull.

It has also been suggested that it 'feeds' harmful bacteria that have been found in the guts of people with colorectal cancer, fuelling the growth of the disease. 

Frozen fruit and yoghurt instead of ice cream 

Rather than eating a couple of scoops of ice cream containing about 20g of sugar and 200 calories, Dr Van Tulleken simply eats some frozen fruit mixed in with a bit of yoghurt. 

Making this swap from ice cream could save you about 70 calories. 

He even admits to adding a small amount of sugar to the fruit if it needs it, but he always opts for natural yoghurt over flavoured. 

That's because flavoured, sugar-free and low fat yogurts are ultra-processed, as they contain artificial substances to boost taste, colour and overall appeal.

Some also contain stabilisers and preservatives, which are designed to keep them fresher for longer on supermarket shelves.

Snack on nuts instead of crisps 

If you find yourself craving a salty snack, instead of opening a packet of crisps try eating raw nuts with a pinch of salt. 

A 25g packet of crisps contains 0.34g of salt and 130 calories, while a pack of salted roasted nuts of the same weight contains about 160 calories and 0.14g of salt. 

However, a healthier snack is just a handful of plain raw nuts, which contains about 150 calories and less than 0.1g of salt. 

Dr Van Tulleken said that he could eat an entire tub of salted nuts in one sitting, but plain nuts are far less moorish.

Oven cooked wedges over frozen chips

Chopping up a potato and cooking it in a bit of oil, salt and pepper is far better than eating a portion of oven chips, Dr Van Tulleken said.

A portion of frozen chips is about 200 calories, but if you make your own using a potato and a drizzle of olive oil it's only 150 calories — saving you about 50 calories. 

Cooking your own also means you avoid added preservatives. 

Dr Van Tulleken explained frozen chips are not just a potato and a bit of oil, many bags of chips are covered in the additive maltodextrin and flavourings.

Maltodextrin, is a powder made from corn, rice, potato starch, or wheat, but which is highly processed. 

It has a high glycaemic index (GI) value, meaning it can cause a spike in your blood sugar. 

The chemical is safe to consume in very small amounts, but people with diabetes should be particularly mindful of how much they consume, experts say.