A nutrition scientist explains the health effects of some commonly misunderstood products.

Some pre-packaged foods, such as pasta and rice, are staples that many of us eat as part of a balanced diet. Others, such as crisps and sugary snacks, are clearly not health foods. But for some packaged and processed foods, the claims on the label can make it hard to decide what’s healthy and what isn’t.

With a recent study showing diets high in ultra-processed foods increase the risk for more than 30 health outcomes – including cardiovascular disease, metabolic disease and even mental ill-health – the level of processing and its effect on our bodies is being considered more and more.

All foods can be part of a healthy balanced diet, but not all foods are equally nutritious. It’s important not to base your nutrition plans on claims made on food labels, but to consider how you consume these foods in the wider context of your life and goals. We all have different health, financial, work, time and other life pressures.

Similarly, there’s no need to panic based on headlines that claim certain foods can lead to a ‘50 per cent increase in the risk’ of one disease or another. This can make it sound like your personal risk is doubled, but this isn’t the case – such figures are based on relative risks for the whole population, not individuals.

This means such percentages aren’t absolute. They’re dependent on how much of a food is eaten, how frequently it’s eaten, what else is eaten and what the overall likelihood of the disease is to start with.

Nutrition doesn’t exist in a vacuum, but understanding the evidence, exaggerations and context can help us make healthy choices. Here are some of the more commonly misunderstood products we can find on our supermarket shelves:

‘Premium’ ready meals

Ready meals such as lasagne, cottage pie and curries labelled with phrases like ‘finest’ and ‘best’ are marketed as premium fail-proof shortcuts to a balanced meal. At first glance, the ingredients look pretty good, with foods such as pasta, meat, cheese and spices listed. But cooking these dishes from scratch at home is still a better option nutritionally.

Ready-made meals often contain added preservatives and stabilisers and are particularly high in salt for stability, food safety, and flavour enhancement purposes.

Creating ready-made dishes is easier and cheaper if the manufacturers use fewer ingredients. This leads to these ‘meals’ often being imbalanced, and low in vegetables.

Also, if you cook at home there are more opportunities to add vegetables and wholegrains to whatever you are preparing. Similarly, you could try adding vegetables to a ready-made meal to balance nutrition with convenience.

Plant milks

Plant milks are marketed as ‘alternatives’ to dairy – we use them in the same way as cow’s milk and having ‘plant’ in the name makes them sound like a healthier option. But they aren’t nutritional equivalents.

Dairy is minimally processed, whereas plant milks are ultra-processed. The plants are heated, juiced, powdered or extracted and reconstituted in water at levels as low as 2 per cent. Key nutrients like calcium are added after but sink to the bottom – if the carton isn’t shaken well and often, they won’t make it out.

When it comes to health benefits, it’s hard to say what the outcomes really are. Plant milks are essential for people who can’t or don’t want to drink traditional milk, but the long-term effects of their consumption simply haven’t been studied enough – most of the evidence comes from studies on the whole plants themselves, not the milk made from them.

Meat substitutes

Like plant milks, meat substitutes wear health halos based on being “made from plants.” But crisps, vodka, and sweets are all technically made from plants too. Any benefits come from eating plants in their natural form, not plant ingredients processed into artificial meat.

Eating less meat, particularly processed meats, has been shown to improve overall health. But what you replace meat with contributes to any potential benefits.

Meal replacement drinks

These drinks claim to provide complete nutrition, with calorie-controlled portions and minimal effort required in their preparation. This is true, and in some situations, such as illness or injury, low appetite, or simple convenience can make them a necessity.

However, while they do contain all the essential nutrients our bodies need, they are lacking in several other ways. Natural foods also contain ‘bioactives’, which are compounds known to promote health. Meal replacements also lack diversity, which is important to help us enjoy what we’re eating and for spreading any risk of consuming the same thing over and over. So, it’s important that they are balanced with other foods and that professional advice is sought if they’re relied upon heavily.

Breakfast cereals

These can be a mixed bag in terms of nutrition and health. Some are minimally processed, low in sugar and linked to health benefits, such as oats and shredded wheat. But others are highly processed and high in sugar, making them more like dessert than breakfast.

However, some studies have linked the consumption of breakfast cereals to better overall nutrition. So again, the context of the whole diet matters.

Granola/protein bars

This is a highly variable area of products. Bars can be highly processed and high in salts, sugars, and additives, but again context plays a large part. If these bars are replacing whole foods, they probably aren’t a health-promoting choice, but if they are replacing ‘junk’ foods, then they could provide some benefits. For some people, on some occasions, the convenience, shelf stability and predictability of bars can help. But for most of us, these probably aren’t a nutritious everyday staple.