Protein bars are a fast and convenient way to get more protein – which can increase protein synthesis, muscle mass and keep fat off.
There are many health and performance benefits associated with a high protein diet. Despite this, protein intake across America (and many other countries) is well down across most populations (1).
Due to the increased need for protein when exercising at a higher intensity, studies have estimated that an athlete requires twice as much protein per day as a sedentary person (2).
If you are participating in regular exercise, then your protein intake should increase to match the new requirements.
Protein bars are an increasingly popular way to increase your daily protein intake. They are mostly made using whey protein, though some use casein protein, or a combination of the two (known as milk protein).
The purpose of this guide is to discuss the benefits, side effects, and recommended daily intake of protein bars, by specifically looking at the protein content. So, for the most part, the benefits will relate to whey protein, but as some protein bars contain creatine, and others contain high levels of carbohydrates we will also look at how the different ingredients interact and what benefits/side effects they have.
Most protein bars will contain around 20g of protein, 40g of carbohydrates, and 10g of fat. But this can vary massively between bars. A lot of bars use high amounts of fibrous carbohydrates as these are seen as calorie-free and means that they don’t have to count them as carbohydrates (which is good for marketing). There are lots of benefits of a high fiber diet though so this is not a bad thing.
Considering that protein bars are high in protein and high in fiber, it is understandable that they are seen as a great appetite suppressing food choice. This means that a lot of the benefits that are associated with protein bars are weight loss related. Protein is also effective at increasing muscle size, strength, and recovery, and improving sporting performance. There are also a lot of other benefits that you might be surprised by.
Protein bars can lead to Increased muscle protein synthesis. Muscle protein synthesis is essential for anyone exercising (or not exercising) due to it providing muscle growth, repair, and maintenance. When you exercise your muscle fibers can become damaged and inflamed.
The body transports protein to the muscle cells to fuel recovery, while recovering the fibers are rebuilt stronger and bigger than before.
There are many ways to increase muscle protein synthesis, bodybuilders use insulin and growth hormone to stimulate protein synthesis (3).
But none of these are as important as raised protein intake. A protein bar can contain between 10 and 30g of protein in a single serving. Eating one either before or after a workout will lead to increased muscle protein synthesis.
Raised muscle protein synthesis can lead to increased strength and power. This is such a well established benefit that you’d think that the evidence would be overwhelming. On the contrary, the evidence is rather mixed. Some studies have found that increasing protein can lead to increased strength and power, but the difference was not significant (6).
Another study found that increasing protein intake helped improve a 1 rep squat by 22% and a 1 rep bench press by 42%, but concluded that the differences were also not significant (7).
A further study found a small increase in hypertrophy and muscular strength in men who increased protein by 25g over the course of 14 weeks (8).
On the other hand, one study in the found no difference in strength or power gains 9. Nor did a study in 2009, though this was only on a 10 week training program which may have been a little short to truly assess changes (10).
While the evidence does support the belief that taking adequate protein increases strength, there does not seem to be much evidence that increasing protein will lead to huge gains in strength and power.
Protein bars can help increase lean mass. When we say lean mass, we’re talking muscle mass for the most part. Obviously by increasing muscle protein synthesis, a protein bar can help to build muscle mass.
A 2000 study on overweight police officers following a calorie deficit diet with increased protein intake found that the protein groups had increases in lean mass compared to the control group (dieting without increased protein) (11).
A 2001 study found that for lean mass to increase, muscle protein synthesis needs to exceed muscle breakdown (12).
Raising protein through a protein bar would appear to solve this issue. A 2014 study by Van Loon stated that protein ingestion “directly elevates muscle protein synthesis” which can help lead to increased lean mass (13).
But it’s not just whey protein that can be effective at increasing lean mass, a study on casein protein (another common protein source for protein bars) found that taking it before bed time helped increase protein synthesis more than whey protein (14).
This means that a pre-bed protein bar might be a good idea.
If you’re wondering whether the amount of protein that is within a protein bar is enough to stimulate protein synthesis, a study in 2013 found that 20g of protein is sufficient to maximally stimulate protein synthesis (15).
Just make sure that your protein bar contains at least 20g (or eat two).
Protein bars can improve your recovery after an intense workout. Due to the high intensity of resistance exercise, your body can take a while to recover. Studies have shown that protein can play a key role in post-exercise recovery (16).
A study in 2005 found that whey protein and leucine were more effective than a carbohydrate solution at maximizing protein synthesis (required for recovery) (17).
Protein bars can lead to a reduction in body fat. There are three different ways that protein can help lead to weight loss, and more specifically fat loss. It can increase your metabolism slightly to create a calorie deficit. It can increase satiety which will prevent hunger. Protein may reduce ghrelin levels, which is known as the hunger hormone.
Studies such as a 2003 study have found that when reducing carbohydrate intake and increasing protein your body composition will improve (18).
A study in 2004 found that a high protein diet can increase thermogenesis, satiety, and improve weight loss (19).
Another study found that a combination of resistance exercise and increased whey protein intake led to greater fat loss results (20).
A 2011 study found that whey protein (but not soy protein) led to significant weight loss and improved body composition in overweight and obese adults (21).
Another study in The Journals of Gerontology found that increasing protein while in a calorie deficit led to improved body composition, this was because the protein prevented muscle loss and increased fat loss (22).
This last point is why protein is so important during weight loss, studies have continually shown that high protein levels during a calorie deficit diet can protect lean mass while fat is reduced (23).
Another study found that twice as much protein as recommended was optimal for the protection of lean mass during a diet (24).
Protein bars reduce appetite (by decreasing ghrelin and increasing satiety). A study in 2011 found that whey protein had a small but significant effect on ghrelin (known as the hunger hormone) (25).
By lowering ghrelin, you are reducing your appetite and preventing further snacking. Of course, whey protein can also increase satiety (how full you feel after eating). Combine these two together and that one protein bar can make a big difference to your diet.
Protein bars stabilize blood sugar. Stabilizing blood sugar is important for many reasons, it can prevent overeating (binging), and can help diabetics. It can also improve concentration, and help you feel better generally. A 1997 study described the benefits of whey protein and its effect on blood glucose levels, finding that it stabilizes blood sugar after consumption (26).
Protein bars can help improve heart health and reduce the risk of diabetes. Studies have found lots of evidence to support the theory that milk protein can help reduce the risk of metabolic diseases such as diabetes, obesity, stroke risk, and similar conditions (27).
A 2013 study found that whey protein can help combat obesity and type II diabetes through the benefits we mentioned earlier: increased satiety, increased thermogenesis (raised metabolism), and reduction in blood glucose (28).
Protein bars that are high in fiber can help reduce blood pressure. A 2001 study shows that a diet high in protein and fiber can reduce blood pressure in people with hypertension (protein bars contain both) (29).
Another study in 2012 found a slight reduction in cardiovascular risk factors among overweight subjects and a slight reduction in blood pressure – but only when combined with resistance exercise (30).
Another study failed to find any difference in blood pressure after a high protein meal, but they were only studying the acute effects (immediately after a meal) rather than looking at long term change, so these results should be taken with a pinch of salt (31).
Protein bars may help lower LDL and total cholesterol levels. Low density lipoprotein (LDL) cholesterol is known by many as “bad” cholesterol. Lowering it can improve your health and reduce your risk of heart disease or strokes. Studies have demonstrated that increasing your protein intake can reduce LDL cholesterol, reduce total cholesterol, and reduce triglycerides (32 33 34).
Protein bars can strengthen bones. A 2011 study found that protein and calcium work synergistically to increase bone density, most protein bars also contain high amounts of calcium (35).
While low protein diets linked to increased bone loss (36).
Another study found that there was a small increase in bone density in men who took whey protein (37).
However not all studies found a connection, this 2011 study found no significant improvement in bone mineral density (38).
Protein bars that contain creatine may lead to greater lean body mass gains. While not all protein bars contain creatine (in fact it is quite rare), there are still quite a few brands out there that do. Studies have shown that protein and creatine work synergistically to promote greater strength and muscle gains than whey protein alone (39).
What are the side effects of protein bars? There aren’t any really. It’s just a chocolate bar with added whey or casein (or both) protein powder. There’s also a lot of fiber in some of them. Each bar will only contain around 20g of protein as a maximum, so even if there were issues around high protein diets, this would hardly qualify!
Protein bars may contribute to a high protein diet, which might lead to increased mortality risk. The only real issue with high protein diets that hasn’t been completely debunked (like renal issues) is the link between high protein diets and death in younger people. A 2014 study found that high protein diets in people under 65 led to increased risk of mortality (40).
But people over 65 actually benefited from the increased protein, so what do we do with that information?
Ideally, a high protein diet should be followed for a short to medium term time while dieting or looking to build muscle. But afterwards, drop down to a slightly lower protein diet. But even this advice has hundreds of issues with it, and more evidence definitely needs to be found before we can say anything definitive.
How many protein bars you consume depends on many things, firstly it depends on the protein content of the bar in question. If your protein bar contains 5g of protein, then you’re going to need more than one to maximally stimulate protein synthesis. If your bar contains 25g per serving, then you’ll probably be best sticking to just the one.
Another factor is how much protein the rest of your diet contains. If you are already consuming lots of protein, then one bar would be sufficient. On the other hand, if you find that you are constantly well below the recommended daily allowance, then two bars might be a good idea.
In one of the best studies in years, Eric Helms, Alan Aragon, and Peter Fitschen laid out how much protein is required for a natural bodybuilder based on current studies (41).
They estimated that you would need 2.3-3.1g of protein per kg of lean body mass (your current body weight minus body fat). Examine.com recommends around 1.5-2g of protein per kg (42),
Other studies have recommended around 1-1.2g of protein per kg of body weight (43).
As you can see, there is a lot of debate around this subject. Obviously, the natural bodybuilding recommendations are not aimed at regular people, but the 1-1.2g of protein seems much lower than any other recommendations. You should probably aim for the 1.5-2g allowance that examine.com recommends, with more if you train regularly.
For a 70kg person this would equal between 105-140g of protein per day.
One thing that you should consider is how well spaced out your protein intake is, a study in 2014 found that most people tend to eat the majority of their protein at dinner, while barely having any at breakfast or lunch (44).
Considering most people work out before dinner, you should think about evening this out a bit.
A protein bar is a good option here because it can be eaten with breakfast or with lunch, or as a pre/post workout snack. At around 20g of protein it is also perfect for maximizing protein synthesis.
Q: Are protein bars healthy for you?
A: It depends. There are healthy protein bars, and then there are some that might as well be a Snickers — considering how much sugar they contain, Their wrappers make it easy to think that they’re healthier than a candy bar, but sometimes they’re not. In reality, they could have even MORE calories
Q: Can I replace a meal with a protein bar?
A: You might substitute a protein bar for a meal, hoping it will help you trim calories and lose weight. Popular diet plans may actually direct you to substitute a protein bar or meal for whole foods at lunch or breakfast. Some choose a protein-bar meal after a muscle-building program at the gym, for convenience.
Q: Are protein bars bad for weight loss?
A: Protein bars in lieu of a proper meal may aid in weight loss, but that may be due primarily to a decrease in calories rather than to the bar itself. Many protein bars are less than 300 calories, which is the number of calories typical of a snack, not a meal.
Q: Are protein bars and energy bars the same?
A: Protein bars are not energy bars. Energy bars contain mostly carbohydrates – often in the form of sugar. They give you quick-fix energy but can leave you feeling tired and hungry soon after. Protein bars contain relatively low amounts of carbs – the nutritional emphasis being on protein.
Q: Are protein bars healthy for breakfast?
A: Protein bars can be a quick, nutrient-dense breakfast, but they shouldn’t be your go-to morning meal. Applegate recommends eating real food, such as fruits and vegetables, most of the time and reserving a protein bar for an occasional breakfast meal.
Q: Are protein bars keto?
A: Unless it directly says it on the label, protein bars generally are not keto safe.
Q: Do protein bars cause acne?
A: It is that protein bars can cause acne since milk-derived protein has been linked to acne breakouts.
Q: Do protein bars cause kidney stones?
A: Consumers of protein shakes and bars should be aware that these convenient edibles can increase your risk for kidney disease and/or kidney stone formation. They do not however guarantee you will have kidney stones.
While perhaps not being as effective as a protein shake, protein bars do have a number of benefits. Particularly the fact that they are actual food rather than a powdered drink, many of them taste nicer too, and are a great replacement for regular junk food options. As contributors to a high protein diet, they offer a lot of benefits.
Increased protein synthesis, bigger muscles, increased strength and power, improved recovery. A reduction in the risk of metabolic diseases, and potentially an increase in bone mineral density. Their ability to regulate blood sugar (thanks to high protein and high fiber content) can really help with weight loss, as can their ability to reduce hunger and increase satiety.
The side effects of protein bars are essentially non-existent. Like any food, moderation and control is key. Just because something is designated “healthy” or “high protein” it does not mean that it can be over consumed.