Overall they found that while these substitutes are usually lower in kilojoules and saturated fat, and richer in fibre, they were also often higher in sugar and sodium. The levels of micronutrients like vitamin B12, iron and zinc varied widely, but many products fell short when compared to similar meat options.
Researchers say that understanding the nutritional implications of these popular substitutes is important as the 'health halo' effect has lead to a perception of nutritiousness that might not be entirely justified.
"Whilst reducing intake of meat has proven health benefits for many individuals, plant-based protein substitutes are not necessarily healthier," Chloe McLeod and Jess Spendlove, dietitians and owners of Health & Performance Collective, told Women's Health. Although most fit the nutritional guidelines and beat meat when it came to sodium and saturated fat content, Spendlove and McLeod say they're not as rich in protein.
"For example a 100g plant based burger patty would only contain 9.6g protein. Average protein per 100g was 9.6 - 14.5g. For a meal, it is usually recommended to consume 20g of protein to assist with maintaining muscle mass."
Clinical nutritionist and author Jess Sepel also explains that the protein sources are absorbed differently by our bodies.
"Both sources of protein have different amino acid profiles," she told Women's Health. "It can be more challenging to get enough of certain nutrients including zinc, omega and Vitamin B12 from plant sources of protein, which is why many vegans decide to supplement, and the protein in these vegan protein sources is also less easily absorbed by our bodies. You can get around this though, it’s possible to get all the amino acids your body requires from plant sources of protein, it just requires a bit more planning."
Aside from what they lack, Sepel also points out that highly-processed pre-packaged products often add plenty of unnecessary extras.
"These alternatives usually have added sugar, thickeners, flavourings and other additives, so it’s important to read the labels carefully and look for ingredients you recognise – not all packaged products contain these nasties!"
Environmental factors can play a major role in the decision to switch out meat, but that's not so straight forward when shopping for replacements.
"It is also important to consider the environmental impact packaged, processed plant based options have as well," Spendlove and McLeod explain. "Many of these products have been imported – 39% according to the study."
However, this isn't a disparagement of eating a plant-based diet, Spendlove, McLeod and Sepel suggest opting for minimally processed whole foods instead of packaged ones.
"Legumes, nuts, seeds and whole grains are great sources of plant-based protein, and tick both nutrition and environmental boxes when assessed as whole foods," Spendlove and McLeod say. "Choose Australian made and sourced products with minimal packaging to reduce environmental footprint, or make your own vegan options, such as making your own vegan patties."
"Chickpea tempeh is one of my favourite vegan sources of protein," Sepel adds. "And beans, nuts, nut butters and seeds are also high protein vegan foods."
"I always encourage people to consider why they are following a vegan diet – if it is for ethical or health reasons, that’s fantastic. However if it’s because a vegan diet is ‘trendy’, then it may not be the best diet for everyone. I advise if you decide to adopt a vegan diet, do so under the guidance of a nutritionist or practitioner to ensure you’re getting all the nutrients you need and your body is supported."