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Weight Loss Coach and Owner at 9 To 5 Nutrition
Joe is an online weight loss coach, certified nutritionist and qualified personal trainer who helps busy, lawyers, marketers and accountants lose weight and keep it off forever.

He specialises in working with people that have busy lives and don't necessarily have time to exercise and cook complex nutritious meals. Having had a 9-5 desk-job, Joe understands the struggles of juggling a hectic life with trying to maintain a good physique.

Joe has helped over 100 professionals lose weight and feel better about themselves using simple, repeatable daily habits and an easy-to-use spreadsheet to track everything.

Joe has also been quoted on several respected sites including Nike, Live Science and

While Joe mainly works online these days, he also offers 1-2-1 personal training sessions across Sussex and Surrey.

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Protein bars have increased in popularity, particularly in the last ten years. 

I remember buying some of the first bars that were available from Holland and Barrat back in the day that took about 3 hours to eat because they were chewier than dried superglue.

Things have moved on a lot since then and the bars available now come in all sorts of delicious flavours and some of them have a texture much more closely resembling a good old fashioned chocolate bar.

In fact, while protein bars are still not quite as popular as whey protein powder, they are now growing at a faster rate and even catching up.

Google Trends for Protein Bars

As the market matures, however, skepticism has grown and many people are questioning the health aspects of protein bars – what do they do, are they actually any good for you, and are they worth the money?

See below for all the answers to your burning questions.


Like whey protein powder, protein bars are not magic and they don’t ‘do’ anything special for your physique or overall performance.

What they do offer is a very convenient and very tasty way to access a decent amount of protein (depending on the bar you choose) when you’re on the go.

Protein bars are available at pretty much any petrol station or newsagents these days (at least in the UK) so they are not hard to come by.

protein bars on sale in petrol station

Are They Good for Bodybuilding?

As mentioned before – if you are aiming to build muscle then you need to be getting a certain amount of protein (around 1.5g per kg of body weight) per day. If a protein bat helps you reach this target, then yes, protein bars can absolutely be good for bodybuilding goals.

Just be aware that it doesn’t really matter too much where this protein comes from (as long as it’s a complete protein source, i.e. meat, dairy, eggs or whey), and there are plenty of cheaper options out there than protein bars. 

Are They Good for Losing Weight?

In order to lose weight, you need to be eating fewer calories than you use every day (i.e. in a calorie deficit). If a protein bar or bars make up some of your calorie intake, then that’s fine. 

Increasing protein generally can be a good thing for weight loss because it will help you feel fuller and your body uses more energy digesting protein.

If you really enjoy protein bars and they help you stick to your calorie target, then yes, protein bars can absolutely help with weight loss

Are they Good for After a Workout?

A protein shake is likely to be a better choice after a workout due to the quality of protein (whey instead of a whey/soy mixture), it also digests more quickly owing to the fact that it’s liquid.

Having said that, if you don’t have access to a whey protein source then a bar is a lot better than nothing.


Surprisingly there are actually a lot of downsides to protein bars.

The first is that they’re very expensive. One of the most popular bars in the UK is Grenades Carb Killa – these can cost anywhere from £2-3 which is a LOT for only 20g protein when you consider that you can pick up 1kg of whey protein for around £20

This contains around 50 servings of the same amount of protein, meaning that the same amount of protein from whey could cost just 40p.

If you’re on a budget, whey protein is an absolute no-brainer. 

The other big negative with protein bars is the amount of protein they pack. Most only have around 20g – this is only just enough to stimulate muscle protein synthesis (the process of turning dietary protein into muscle). 

If you’re serious about building muscle, you really need to be looking at getting a minimum of 1.5g of protein per kg of bodyweight. This means getting in a minimum of 120g of protein per day for an 80kg person, so even the bars that are highest in protein would only provide 17% of daily requirements.

Not bad but not amazing either.

Most protein bars also pack around 200 calories. For context, you could get 20g of protein from Whey Protein or Zero Fat Greek Yoghurt for just 100 calories.

The other potential issue with protein bars is the type of protein they contain, The ingredients of each individual protein bar varies but many contain an amount of soy protein (see the Carb Killa example below)

Carb Killa Protein Bar White Chocolate Cookie Ingredients

Soy protein is likely inferior to whey when it comes to stimulating Muscle Protein synthesis – this study showed that amino acid concentration in the blood was 18% higher after the consumption of Whey vs Soy.

If you are really trying to maximize the amount of muscle you build or maintain then it’s best to stick to supplements that contain as close to 100% whey protein as possible.


In theory, you could eat 10 protein bars in a day and get around 2000 calories and 200 grams of protein. Not bad, but you’d also get a huge amount of fiber – about 70g, which is WAY over the recommended 30g which could cause bloating, gas, and constipation – not ideal.

Protein bars also contain polyols or sugar alcohols(more on this below) and overconsumption of this could lead to other gut issues since they can have a laxative effect when overconsumed.

For this reason, I wouldn’t recommend more than 2-3 bars per day, even if you really like them and money is no object. This is because you need to leave some room in your diet for the fiber that comes from fruit and vegetables.


You’re probably looking at that ingredients list wondering what the hell a ‘polyol’ is. This is a type of carbohydrate like sugar but is actually a ‘sugar alcohol’.

Some examples of Polyols include;

  • Xylitol 
  • Sorbitol
  • Mannitol
  • Maltitol
  • Isomalt

These are typically present in sweetened drinks and sugar-free chewing. Despite the name, sugar alcohols don’t contain any sugar, and while they taste similar, they have a much lower glycemic index than sugars like sucrose or glucose.

This means that the energy from Polyols is released more slowly into the bloodstream which doesn’t spike insulin as much and could help you feel fuller for longer.

Another benefit of Polyols is that they contain fewer calories than regular sugars. Sugars generally contain 4 calories per gram whereas Poyols can contain as little as 2 calories per gram, meaning that in some cases they’re half as calorific as sugars.

The fact that protein bars generally use Polyols over sugar (as well as the protein content, obviously) makes them a good option for anyone trying to increase the amount of protein in their diet and/or reduce calories – which should probably be most people.


So, are protein bars healthy?

As with most things in nutrition and fitness, there is no definitive answer, but for the most part, there is nothing wrong with most people consuming 1-2 bars per day, as long as they fit into their overall goal, whether that’s muscle-building or weight loss. 

Be aware that there is definitely no requirement for protein bars in anyone’s diet, and the same benefits can be derived from cheaper supplements (e.g. whey protein powder) or regular food (dairy, lean meat).

For me, I use protein bars as a go-to snack if I’m on the move and want something that tastes good with a bit of protein, so I’ll grab one from a shop or garage if I’m on the go.

If you want to know what the best protein bars are, I’ve reviewed over 20, so take a look


  • Most of them taste really good
  • Conveninet – no need to refrigerate or do any prep before eating
  • Available almost everyhwere (at least in the UK)
  • They contain a decent amount of protein
  • They are made with Polyols rather than Sugar which is better for a whole host of reasons (see above)
  • The polyol and fiber content mean they’re quite filling


  • They’re expensive
  • Most are made partly with soy protein which isn’t optimal for muscle building
  • The same amount of protein can be obtained for fewer calories from other foods


Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men:

A Systematic Review of the Effects of Polyols on Gastrointestinal Health and Irritable Bowel Syndrome:

Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties:

2.12 Sugar Alcohols (Polyols, Sugar Replacers):

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