SlimrChat reviewed: The best protein bars for weight loss & nutrition

Ed Milner | Last update: 1st June 2025

Not all protein bars for weight loss are created equal, especially if you’re looking for the best protein bars for weight loss UK. Many are loaded with sugar, artificial sweeteners, or low-quality protein. So what makes a good protein bar? Let’s break down some of the key factors:

1. Protein content & quality

• Amount: Aim for at least 15-20g of protein per bar for a satisfying and effective option.
• Source: Look for high-quality protein sources like whey protein isolate, milk protein, casein, pea, or soy protein rather than collagen or gelatine, which are lower in essential amino acids.

2. Sugar & sweeteners

• Low Sugar: Ideally, the bar should have less than 5g of sugar. Many bars use artificial sweeteners or sugar alcohols (e.g., maltitol, sorbitol, erythritol), which can cause digestive issues in some people. 
• No Hidden Sugars: Avoid bars with high fructose corn syrup, glucose syrup, or added syrups disguised under different names (e.g., rice syrup, agave).

3. Fibre content

• A good protein bar should have at least 3-5g of fibre to support digestion and keep you fuller for longer. Look for oats, chicory root fibre (inulin), or nuts/seeds as fibre sources.

4. Fat quality

• Healthy Fats: Prefer bars with unsaturated fats from nuts, seeds, or coconut, rather than those high in saturated fats from palm oil or butter.
• Avoid Trans Fats: Check for hydrogenated or partially hydrogenated oils, which should be avoided.

5. Calories & portion control

• If you’re using the bar as a snack, aim for under 250 kcal.
• If it’s replacing a meal or post-workout fuel, 250-350 kcal is more reasonable.

6. Artificial ingredients & additives

• Avoid bars loaded with artificial flavours, colours, preservatives, or excessive emulsifiers (e.g., soy lecithin, carrageenan).
• The fewer ingredients, the better!

7. Purpose of the bar

• Post-workout recovery? Look for whey protein, a moderate amount of carbs (15-25g), and some electrolytes.
• Weight loss? High protein, high fibre, low sugar options are best.
• Meal replacement? A balance of protein, healthy fats, and fibre is important.

8. Taste & texture

• Some bars have a chalky or overly chewy texture due to excessive protein powders. Test a few to find one you enjoy!

We’ve selected some of the more popular protein bars available in the UK and to help you choose the best, we’ve ranked bars based on the following strict criteria:

✅ 20g+ of protein (for muscle maintenance and satiety)
✅ Under 200 calories (suitable for weight loss goals)
✅ Less than 2g of sugar (avoiding unnecessary sugar spikes)
✅ Fibre content (for digestion and fullness)
✅ Bar weight (to compare fair portion sizes)
✅ Availability (whether widely stocked in UK supermarkets or online-only)
✅ Added vitamins & minerals (bonus for extra health benefits)
✅ Flavours available (variety and taste factor)
✅ Vegetarian & vegan-friendly options
✅ Manufactured in the UK (for quality control and transparency)

Source: Manufacturers own websites, April 2025 / Nutritional information shown per serving/bar

Detailed Reviews & Pros/Cons

(Nutritional information per serving/bar)

1. Holland & Barrett Protein Bar (60g) (Rank #1)

✅ 21g protein
✅ Lower sugar (1.5g) and lower calories (194)
✅ High fibre (6g)
❌ Only available in Holland & Barrett

2. Grenade Carb Killa (60g) (Rank #2)

✅ 21g protein
✅ Low sugar (1.3g)
✅ Widely available
❌ Higher calories (222) & lower fibre (2.4g)

3. Fulfil Vitamin & Protein Bar (55g) (Rank #3)

✅ 19.5g protein, 203 calories
✅ Added vitamins
❌ Higher sugar (2.1g)

4. Barebells Protein Bar (55g) (Rank #4)

✅ 6g fibre
✅ Widely available
❌ Lower protein (16g), higher calories (217)

5. Misfits (50g, Vegan) (Rank #5)

✅ 180 calories
✅ Low sugar (0.89g)
✅ Best vegan option
❌ Lower protein

6. Huel Complete Nutrition Bar (51g) (Rank #6)

✅Higher fibre (5.8g) & added vitamins
✅ Full nutrient spectrum
❌ Lower protein (13g)

7. Eat Natural Protein Fruit & Nut Bar (40g) (Rank #7)

✅ Lower calories (198)
✅ Widely available & UK-made
❌ Higher sugar (7.9g) and lower protein (10.4g)

8. Trek Protein Flapjack (50g) (Rank #8)

✅ Widely available
❌ High sugar (12g) & lower protein (10g)

9. Nakd Protein Bar (45g) (Rank #9)

✅ Higher fibre (6.8g)
❌ Low protein (7.6g) & high sugar (13g)

Final Thoughts: choosing the best protein bars for weight loss UK

If you’re looking for the best all-round protein bar for weight loss, our view is that the Holland & Barrett Protein Bar takes the top spot, delivering high protein, lower sugar, and high fibre. The Grenade Carb Killa is an excellent pick with great taste, just missing out on the top spot with a lower fibre count. For added vitamins, Fulfil is a good option, while Misfits is the go-to plant-based option.

If you’re still unsure which one to try first, our ranking of the best protein bars for weight loss UK is a great place to start.

The key takeaway? Look for high protein (20g+), low sugar (<2g), high fibre (+4g) and lower calories (<200 kcal) while considering the actual bar weight for portion fairness.

As one of our members said, ‘If it looks like candy, tastes like candy…it probably is candy!’ It is worth paying attention to the nutritional information as some of the bars on the market are relatively low on protein and higher on sugar….so be aware.

When considering these types of products for a protein boost, be aware that the positive boost of protein is probably off-set by the other processed ingredients. If you’re looking for healthy, unprocessed, high-protein snackable foods, here are some great options:

1. Nuts & seeds

• Almonds (6g protein per 28g)
• Pumpkin seeds (7g protein per 28g)
• Walnuts (4g protein per 28g)
• Chia seeds (4g protein per 28g, also high in omega-3s)

2. Dairy-based snacks

• Greek yogurt (10-15g protein per 150g)
• Cottage cheese (13g protein per 100g)
• Cheese slices (7g protein per 30g)

3. Eggs & egg-based snacks

• Boiled eggs (6g protein per egg)
• Egg muffins (portable and easy to make)

4. Lean meats & fish

• Turkey slices (7g protein per 50g)
• Chicken breast strips (10g protein per 50g)
• Tuna in water (20g protein per can)

5. Legumes & beans

• Edamame beans (17g protein per 100g)
• Chickpeas (8g protein per 100g)
• Lentil crisps (around 5g protein per serving)

6. Other healthy high-protein snacks

• Roasted chickpeas (7g protein per 28g)
• Protein energy balls (homemade with oats, nut butter, and seeds)

Our SlimrChat advice is to carry snack sized portions of nuts and seeds as a go-to….wean yourselves off processed foods where you can. What’s your favourite way of boosting your protein intake? Share your experience and tips with the SlimrChat community. Or perhaps you would like to ask the community a question? Click the button below and join the chat now!