Are protein bars healthy? Diet expert names the best ones to grab on the go… and the ones to avoid
These are health food products now available in almost every supermarket, grocer and pharmacy in Britain.
Produced by companies like Grenade, Trek, and Fulfil, protein bars are sold as health-boosting snacks packed not only with muscle-boosting nutrients but also other beneficial ingredients like fiber and vitamins.
And these snacks are becoming increasingly popular in the UK. The protein bar industry is currently worth more than £1.3bn and is expected to continue to grow, with more new brands emerging every year.
But a growing number of experts warn that protein bars also have a dark side.
Last year, TV fitness guru Joe Wicks released a documentary called Licensed To Kill, in which he accused protein bar companies of packaging their products with sugar, fat and ultra-processed ingredients; artificial compounds that research suggests increase the risk of cancer, heart disease and even dementia when consumed regularly.
And research seems to back up Wicks’ claims about protein bars.
A study published in 2025 by Queen Mary University of London found that 37 per cent of more than 450 snack bars (including all protein bars) sold in ten supermarkets were high in sugar, while more than half were high in saturated fat (a particularly harmful form linked to chronic health problems).
Last year, TV fitness guru Joe Wicks released a documentary called Licensed To Kill in which he accused protein bar companies of packaging their products with sugar, fat and overly processed ingredients.
Researchers concluded that customers were ‘misled’ by snack bar companies about the healthiness of these products.
It’s a view shared by London-based nutritionist Pippa Campbell, author of Eat Right, Lose Weight.
‘I’m not a big fan of protein bars in general and don’t consider them a health food,’ says Ms Campbell. ‘There’s a lot of marketing about protein content, but most bars are still overly processed and low on real nutritional value. They can sometimes be useful when traveling or when suitable food is not available, but they should never replace a balanced meal.’
But experts say not all protein bars are created equal. While most nutritionists argue that natural protein-rich snacks like seeds, nuts, eggs and yogurt are better for the body, they say some bars are more nutritious than others.
Ms Campbell gives her verdict on the best protein bars in the supermarket and the ones to avoid. Read on to learn more…
The healthiest protein bars
Fulfill Chocolate Salted Caramel Vitamin and Protein Bar
£2.90 for 55g bar at tesco.com
According to experts, Fulfill protein bars, which are low in sugar and high in protein, are one of the healthier protein bars on offer.
The brand has a variety of flavors including chocolate salted caramel, peanut butter, and chocolate brownie.
Fulfill Chocolate Salted Caramel Vitamin and Protein Bar is low in sugar and high in protein.
The main selling point, which helps it stand out in the crowded field, is that the bars are enriched with nine vitamins.
This includes folic acid, vitamins E and C, as well as four different types of B vitamins.
Each bar is 204 calories, which is slightly more than other competitors. However, this is partly due to its 20 grams of protein, which is higher than many other British bars.
It is also low in sugar, only 1.7 grams. Ms. Campbell says she was impressed by the Fulfill bar.
‘With the addition of vitamins, it is high in protein and its sugar content is quite low,’ he says. However, he notes that its fiber content is relatively low, containing only 3.4 grams.
He also argues that the sweetness in this low-sugar snack comes from sugar alcohols, a highly processed artificial ingredient.
Fast 800 Dark Chocolate Raspberry Protein Bar
£26.99 for 12 x 45g bars at thefast800.com
This raspberry flavored bar is rich in protein and fiber.
Created by specialist meal replacement company Fast 800, the 14 grams of protein and 9 grams of fiber come primarily from peanut butter and chicory root fibre; While these are not completely natural, they are not considered ultra-processed.
Fast 800 Dark Chocolate Raspberry Protein Bar is rich in protein and fiber.
The protein level of these snacks is around average (14 grams) and has an impressively low sugar content of 1 gram.
10 grams of fat is higher than other bars, but experts say it’s largely natural forms of fat. The bar contains 192 calories, which is lower than other competitors.
But Ms Campbell says the product does not contain overly processed ingredients.
It says: ‘It uses quality protein and fibre, but has added sweeteners and contains soya protein isolate, which is a highly refined ingredient.’
Protein Ball Co Blueberry Oat Muffins
£1.85 for a 45g bag at healthysupplies.co.uk
A growing feature on Britain’s snack shelves is protein balls, and health experts say this particular brand is top-rated.
Protein Ball Co has a variety of flavors, including blueberry oat muffin, peanut butter, lemon, pistachio, and salted caramel.
Protein Ball Co Blueberry Oat Muffins are made primarily with natural ingredients.
Experts say that all of their products are produced primarily with natural ingredients.
The blueberry oat muffin flavor is made with dates, almonds, freeze-dried blueberries, gluten-free oats, and flaxseeds.
It is also enriched with vitamins B12, C and D.
These 178-calorie balls are relatively low in protein; It contains only 6.5 grams. 3.6 grams of fiber is also on the more marginal side.
Moreover, 17 grams of sugar and 7.3 grams of fat may seem alarming at first glance.
But Ms Campbell says this sugar and fat comes from natural sources such as dates, which also contain nutrients such as potassium and magnesium, and may be preferable for those who want to avoid overly processed products.
‘These may be lower in protein and higher in natural sugar, but this is primarily due to dates,’ he says.
‘This is one of the least processed options.’
Delicious Ella Roasted Peanut Protein Ball
£1.90 for a 40g ball at Waitrose.com
This product, another protein ball made with natural ingredients, also received full marks from our expert.
It’s made by Deliciously Ella, a food brand named after a social media influencer launched.
Deliciously Ella Roasted Peanut Protein Ball is made primarily with dates, peanuts, and peanut butter
Its three main ingredients are dates, peanuts and peanut butter.
The protein ball contains 150 calories, making it one of the lowest-calorie products available. It also contains only 5.2 grams of fat.
However, it has a lower protein content (4.6 grams) than other similar snacks. Its fiber content is also quite remarkable, with only 5.9 grams.
And like other natural protein balls, it’s high in sugar content (16 grams) due to dates.
But Ms Campbell says she would rather eat it than one of the bars, which are lower in sugar but higher in ultra-processed ingredients.
‘Fibre, sugar and fats come from whole food components,’ he says. ‘It is devoid of artificial sweeteners and refined vegetable oils that you might expect to find in other similar products.’
Pip & Nut Dark Chocolate Pistachio Protein Bar
£4 for 3 x 46g bars at tesco.com
This natural-ingredient bar is relatively high in protein and low in sugar.
Its two main ingredients are peanuts and dark chocolate. It also contains oats.
Pip & Nut Dark Chocolate Peanut Protein Bar contains more protein than other natural bars
It contains significantly more protein (10 grams) than the other natural bars on this list. It also contains less sugar – 10 grams.
But it contains more calories (217) and fat (12 grams). It is also low in fiber; It weighs only 2.7 grams.
And as Ms. Campbell points out, it’s not free from ultra-processed ingredients.
‘It has natural sources of protein and fiber like peanuts and oats, and it’s free of artificial sweeteners and refined vegetable oils,’ she says.
‘Agave syrup is used, which is more refined than people think.’
…And the unhealthiest protein bars
Trek Power Lotus Biscoff Bar
£2.29 for a 55g bar at proteinpackage.co.uk
This protein bar is high in calories, fat and sugar. It’s also full of overly processed ingredients, experts say. Perhaps this isn’t surprising given that it’s based on the taste of a sugary biscuit snack.
The Lotus Biscoff bar is produced by Trek, one of the UK’s most popular protein snack brands, which also sells protein flapjacks in flavors such as cocoa oats, salted caramel, white chocolate and raspberry.
Trek Power Lotus Biscoff has 239 calories, which is higher than most other similar protein snacks.
At 239 calories per 55-gram bar, it’s higher than most other similar protein snacks. Meanwhile, it’s also high in sugar, with 8.9 grams and 12 grams of fat, most of which come from artificial sources.
It contains a significant amount of protein (15 grams) and 8.6 grams of solid fiber, says Ms. Campbell.
But Lotus Biscoff says the bar is full of ultra-processed ingredients. ‘It contains candied sugar syrups, sweeteners and refined vegetable oils such as rapeseed oil,’ he says.
‘I would put this in the highly processed category’.
Grenade Oreo White Protein Bar
£2.70 for 60g bars at tesco.com
It may be the most popular protein bar brand in the country, but experts have little good to say about Grenade’s products.
The UK company has built a brand for itself by selling low-sugar protein bars that mimic the taste of much-loved desserts. This includes the birthday cake flavor and the latest addition, the Creme Egg protein bar.
Grenade Oreo White Protein Bar is one of the popular ones in the country but experts say it is full of ultra-processed ingredients.
The Oreo White Protein flavor is one of their best-sellers, and it’s definitely low in sugar – just 0.7 grams. Its 135 calories are also below average.
However, it contains little or no fiber – 0.9 grams.
And while it’s packed with protein (21 grams), most of that comes from artificial ingredients, experts say.
Ms. Campbell says the bar’s long list of ultra-processed ingredients is reason enough to avoid it. ‘It is low in sugar because it contains sucralose, an artificial sweetener,’ he says. ‘There are also sweeteners and refined vegetable oils. So it’s a very ultra-processed thing.’
