How to Choose a Protein Bar
What to look for in a protein bar - protein content, sugar, ingredients, and when a bar is worth it vs. when whole food is better.
Protein bars are everywhere - from gym bags to office drawers. But with hundreds of options, quality varies enormously. Some are glorified candy bars with a protein label. Here is how to find one that actually supports your goals.
What Makes a Good Protein Bar?
Not all protein bars are created equal. Here is a framework for evaluating any bar:
1. Protein Content: At Least 20g
A protein bar should deliver a meaningful dose of protein - at least 20g per bar. Bars with 10–12g are closer to a granola bar with some protein added. For reference, 20g is roughly equivalent to three eggs or 65g of chicken breast.
2. Protein-to-Calorie Ratio
The best protein bars provide at least 1g of protein per 10 calories. Here is how to evaluate:
| Calories | Minimum Protein | Verdict |
|---|---|---|
| 200 | 20g | Good |
| 250 | 25g | Good |
| 300 | 20g | Acceptable |
| 350+ | 20g | More of a meal bar |
If a bar has 300 calories but only 10g of protein, it is not a protein bar - it is a snack bar with a marketing label.
3. Sugar Content
Aim for 5g of sugar or less. Many bars use sugar alcohols (erythritol, maltitol) or fibre syrups (isomalto-oligosaccharides) as sweeteners instead. These are generally fine, though some people experience digestive discomfort with sugar alcohols in large amounts.
Watch out for bars with 15+ g of sugar - these are closer to chocolate bars in terms of sugar content.
4. Protein Source
Common protein sources in bars:
| Source | Quality | Notes |
|---|---|---|
| Whey protein isolate | Excellent | Complete amino acid profile, fast-digesting |
| Milk protein isolate | Excellent | Blend of whey and casein |
| Soy protein isolate | Very good | Complete plant protein |
| Pea protein | Good | Nearly complete, may affect texture |
| Collagen | Poor for muscle | Incomplete amino acid profile, low in leucine |
Avoid bars where collagen is the primary protein source if your goal is muscle building. Collagen lacks the leucine and essential amino acids needed to maximally stimulate muscle protein synthesis.
5. Ingredient List Length
Shorter is generally better. The best protein bars have 10–15 recognisable ingredients. If the list reads like a chemistry textbook, consider a simpler option - or just eat whole food.
When Are Protein Bars Worth It?
Good use cases:
- On-the-go when you cannot prepare food
- Travel days
- Between-meal snack to bridge a protein gap
- Emergency backup in your bag
- Post-workout when you cannot get to a kitchen
Not ideal:
- As a primary daily protein source - whole foods like chicken, eggs, Greek yogurt, and cottage cheese are better
- If you are eating them like candy - a 250-calorie bar consumed mindlessly every day adds up
Protein Bar vs. Other Quick Protein Sources
| Option | Protein | Calories | Convenience |
|---|---|---|---|
| Protein bar | 20–25g | 200–300 | Very high |
| Protein shake | 25–30g | 110–150 | High (need shaker) |
| Hard boiled eggs (3) | 19g | 216 | High (meal prep needed) |
| Greek yogurt cup | 15–20g | 100–150 | High |
| String cheese (2) | 14g | 160 | Very high |
Bars win on portability but lose on protein-per-calorie compared to shakes and yogurt.
Quick Checklist for Choosing a Protein Bar
- 20+ g protein per bar
- Under 250 calories (or suitable for your calorie budget)
- 5g sugar or less
- Whey, milk, or soy protein as primary source (not collagen)
- Short, recognisable ingredient list
- Tastes good enough that you will actually eat it
The Bottom Line
A good protein bar has at least 20g of protein, low sugar, and a quality protein source. Treat bars as a convenient supplement to your diet, not the foundation. Log them in Protein Pal alongside your meals to make sure they are helping you hit your daily protein target - not just adding calories.