Protein repairs and builds tissue, reduces hunger and may even help with weight loss. Add the magic phrase “high-protein” to the packaging of bread or yogurt – or even ice cream and Snickers bars – and suddenly they wear a health halo.
The global protein bar market is projected to grow from £3.71 billion in 2022 to £5.60 billion by 2029, according to Fortune Business Insights. Once niche products sold in health food shops to athletes and bodybuilders, they are now available everywhere, in supermarkets, convenience stores, even Poundland.
They can contain around 20 grams (about three quarters of an ounce) of protein, providing about a third of the recommended daily protein intake for an average sized person in the UK.
But while they pack a protein punch, most are also high in calories and many are high in unhealthy saturated fats. Most are also classed as ultra-processed foods.
Studies into their health benefits are limited. Naveed Sattar, a professor of cardiometabolic medicine at Glasgow University’s School of Cardiovascular and Metabolic Health, says: “There is lots of good evidence that protein suppresses appetite. But the question of whether protein bars are health-giving in and of themselves has not been trialled yet.”
Rob Hobson, a sports nutritionist and the author of Unprocess Your Life, adds: “People are obsessed with protein, but they confuse ‘high protein’ with ‘healthy’ because they think protein is the most important nutrient to get in your diet.”
He describes many protein bars as a “mishmash of weird ingredients, bindings, sweeteners and emulsifiers, which some studies suggest negatively affect gut biome. They are an ultra-processed food, whatever way you look at it.”
Common ingredients include maltitol, a sweetener that can cause diarrhoea, whey protein, which can cause bloating, sucralose, which can impact on the variety of gut bacteria, and inulin, which is a fibre source that can lead to bloating.
The few studies into protein bars show mixed results. One study by researchers at Arizona State University published last year in the Journal of Functional Foods concluded that daily ingestion of protein bars can “significantly” increase fat mass. A 2021 study of elite athletes concluded that consumption of protein bars improved the athletes’ “physiological adaptation after training”.
Meanwhile, a 2006 study compared the effects that high protein and high fibre bars had on glucose and insulin levels in a cohort of 23 women, and found that glucose and insulin responses – and peak glucose levels – were significantly lower in those who ate bars high in protein and fibre compared with women who had eaten bars high in fat and sugar. A morning high-protein bar also reduced energy intake at lunch by 5 per cent.
Priya Tew, specialist dietitian from Dietitian UK, says that, generally, most of us get enough protein from our regular diets, and recommends against relying on ultra-processed snacks, which most top-selling protein bars are.
“We all need protein in our diets; it is a very important macronutrient, but so are carbohydrates and fats. The key is not to focus on just one nutrient or food group but to aim for balance. The average person is not going to need protein bars daily, but this does not mean that all protein bars need to be excluded, or that all of them are equally nutritious.”
Nine protein bars ranked by taste and health benefits
Grenade Oreo 60g bar
21g of protein, 1g sugar, 233 calories
Sarah Carter is a health and wellness expert residing in the UK. With a background in healthcare, she offers evidence-based advice on fitness, nutrition, and mental well-being, promoting healthier living for readers.
