If keeping the snack’s calorie total down matters most, compare the energy in the whole bar: Kellogg’s UK lists 104 kcal and 1.4g protein for a 27g Special K Red Berry bar. If stated protein matters more, Nature Valley UK lists around 10g protein and 196 kcal for its 40g Peanut & Chocolate bar; check sugars and allergens for the exact product alongside those figures.
If energy per bar is your leading consideration, start with the portion you will eat. A smaller cereal bar may have less protein than a protein-labelled alternative, so compare both figures if protein also matters to you.
If you want a bar with a stated protein amount after the gym, read grams of protein alongside kcal per bar. Check the exact flavour and pack rather than assuming all protein bars have the same nutrition information.
Peanuts, other nuts, milk, soya and gluten-containing cereals appear in the ingredient or precautionary information for some of these bars. Check the current pack for the product you intend to eat.
Start with the portion you would eat, then compare its energy and protein before checking the rest of the label.
| Priority | What to check | Your needs |
|---|---|---|
| Energy per bar | Check kcal for the whole bar or intended serving, then use the per-100g figure to compare products of different sizes. Kellogg’s UK lists 104 kcal for a 27g Special K Red Berry bar; Tesco lists 116 kcal for a 30g Graze Cocoa Vanilla Oat Boost. | I want to know what one bar contributes to my snack, not just how its nutrition looks per 100g. |
| Protein | Compare grams of protein and kcal for the same bar. Nature Valley UK lists around 10g protein and 196 kcal for its 40g Peanut & Chocolate bar; Kellogg’s UK lists 1.4g protein for a 27g Special K Red Berry bar. | If protein is important to me, I need the stated amount for the portion I would eat, as well as its calorie total. |
| Sugars and saturated fat | Read both values for the stated serving and per 100g. Compare the exact flavours you are considering rather than relying on an oat, nut or protein description. | A bar’s name alone does not tell me its full nutrition profile. |
| Ingredients and allergens | Read the current ingredients list, highlighted allergens and any precautionary “may contain” statement. Check the exact flavour and pack. | If I avoid an ingredient or allergen, I need to check that information before choosing a bar, regardless of its calories or protein. |
Nature Valley UK lists 196 kcal for its 40g Peanut & Chocolate Protein Bar, while Kellogg’s UK lists 104 kcal for a 27g Special K Red Berry Bar. Their protein amounts also differ, so the label alone does not settle a calorie-led choice.
Compare protein grams with kcal per actual bar, and decide which figure matters more for this snack.
The researched examples include bars weighing between 27g and 50g. A per-100g comparison does not, by itself, show the energy in the bar you will eat.
Start with per-bar or intended-serving values for energy, protein, sugars and saturated fat; use per-100g values to compare products on the same weight basis.
In its November 2025 audit of 458 snack bars, Action on Salt & Sugar classified 37% as high in sugars and 55% as high in saturated fat under UK front-of-pack thresholds. Those audit figures do not describe every individual bar. Some of the products discussed here also contain, or may contain, relevant allergens.
Read the nutrition and ingredient panels for the exact flavour. If an allergen affects your choice, check its highlighted ingredients and any “may contain” statement before eating.
These examples describe specific bars or documented product lines, not every product sold under each brand.
Nature Valley UK lists around 10g protein and 196 kcal for its 40g Peanut & Chocolate Protein Bar.
Kellogg’s UK lists 104 kcal and 1.4g protein for a 27g Special K Red Berry Bar.
Tesco lists 116 kcal per 30g Graze Cocoa Vanilla Oat Boost.
Myprotein UK lists 10.2g protein and 217 kcal for a 50g TREK Original Oat Protein Flapjack.
Eat Natural UK lists 7.8g protein and 220 kcal for its 40g Peanuts & Dark Chocolate Protein Bar.
A Weetabix Food Co. product list from November 2021 records Alpen Light and Alpen Protein bar lines.
These Joybuy options include smaller cereal and oat bars for a calorie-led comparison, alongside protein-labelled bars for shoppers weighing protein against energy. Compare each exact flavour’s current pack information before choosing.
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For a calorie-led comparison when a large protein amount is not the main aim. Check energy and protein per 21.5g bar, as well as the allergen information for this Dark Chocolate variant.
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For comparing a stated protein amount with the energy in a whole bar. Nature Valley UK describes this 40g flavour as providing around 10g protein; check the current pack’s energy figure and its peanut, soya and milk ingredients.
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A different 40g Nature Valley protein-bar flavour to consider if protein is part of your comparison. Read this variant’s own per-bar protein and energy values, and check its nut, soya and milk allergen information.
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For comparing the energy in one 30g oat boost with other snack portions. Check the Lemon Blueberry variant’s protein and sugars per boost and read its ingredient and allergen information.
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Another 30g oat-boost flavour for a per-portion energy comparison. Use the Cherry Bakewell pack’s own protein, sugars and allergen information rather than applying figures from a different Graze flavour.
No single calorie figure settles the choice if protein also matters to you. Kellogg’s UK lists 104 kcal and 1.4g protein for a 27g Special K Red Berry Bar; compare both values for the bars you are considering.
Use the per-bar or intended-serving figure to assess what you would eat, and the per-100g figure to compare equal weights. NHS inform explains that nutrition labels show values per 100g and may also give values per portion.
Yes. The specific bars discussed here include ingredients or precautionary statements concerning nuts, milk, soya or gluten-containing cereals. Check the current ingredients list and any “may contain” statement for the exact flavour before eating it.
No: the protein amount alone does not establish either value. Nature Valley UK lists 196 kcal for its 40g Peanut & Chocolate Protein Bar, while Myprotein UK lists 217 kcal for a 50g TREK Original Oat Protein Flapjack. Read the sugars value for each exact bar separately.