Protein Bars

A protein bar is a snack bar built around a concentrated protein source, normally 15 to 25 grams per bar. Protein contributes to the growth and maintenance of muscle mass. The format does one thing well: it makes that protein portable when a meal or a shake is not practical, on a commute, between meetings or straight after training.

Most bars sold in the UK use whey, milk protein or a blend of both. Whey digests quickly, milk protein more slowly, and the blend is what gives layered bars their chew. Plant bars use soya, pea or pea with rice, which together cover all the essential amino acids, the protein building blocks your body cannot make itself. Nut and date bars sit lower, around 8 to 12 grams, and eat more like whole food. One detail worth checking if you buy plant-based products: several well-known bars contain beef gelatine in the nougat layer, so they are not vegetarian.

Sugar, polyols and the texture trade-off

Almost every low sugar bar replaces sugar with polyols, sugar alcohols such as maltitol or glycerol, plus chicory root fibre. That keeps sugar near 1 to 3 grams per bar and adds fibre. It also has a cost: eaten in quantity, polyols can cause wind or a loose stool, which is why packs carry that warning. Texture is the second trade-off. The more protein packed into 60 grams, the denser and drier a bar tends to be, so a soft, cake-like bar usually carries slightly more sugar or fat.

How we choose the protein bars we stock

We judge a bar on three things: the protein source, the amount per bar, and what the rest of the label is doing. We want a named source, whey isolate or a soya and pea blend for example, at least 15 grams of protein, and sugar well below the protein figure. Sweetness from a modest amount of polyol or stevia is fine, syrup as the second ingredient is not. Taste counts as well, because a bar you dislike stays in the cupboard, so we try them ourselves and independent labs spot-check batches. We buy straight from the brands, so what arrives is authentic. Read how we select our brands.

Bars are not the cheapest protein per gram. If you mainly need protein at home, protein powders cost less per 20 grams and let you set the portion yourself. Bars win on convenience: no shaker, no fridge, nothing to measure. Plenty of people use both, powder at home and two or three bars in the bag for the week.

A bar suits you if you find it hard to reach your protein target from meals, if you travel or train away from home, or if you want a sweet snack with more substance than biscuits. Within our wider sports nutrition range we group bars by what they are for:

• 20 g protein and above: after resistance training, or as part of a higher protein day.
• Around 15 g, lower calorie: an afternoon snack when you are watching total energy.
• Nut and fruit based: fewer sweeteners, softer texture, less protein per bar.