Does whey protein make you fat



I saw this question asked on a forum online and thought… Okay, let me address the topic, "Does whey protein make you fat"?

First of all, Whey protein powders are a very very popular way of supplementing your protein content in your diet. Whey is a byproduct in cheese making and is in effect, the left overs of cheese make. So why is it so expensive I hear you say? Well two reasons really, firstly, the marketing that goes behind whey protein powders but the less cynical answer is the filtration process that the left over whey protein has to go through in order for it to be turned into a digestible, mixable and palatable powder that is mostly protein.

Whey protein comes in a lot of types and to go into all the types of whey would be to digress from the topic so we shan't do that.

The reason I wanted to cover this as a blog post topic was because I didn't totally agree with the easy answer which was "excess calories make you fat". That is a far too simplistic way of looking at how our bodies work and how biochemistry works. Sure, excess calories do not help in the battle against the bulge and the debate of whether a calorie is a calorie is a calorie wages on (does the body treat 1 sugar calorie the same as it would say 1 calorie from a very low glycemic fibrous vegetable?) but what happens to excess calories and excess protein.

In order to answer the question "Does whey protein make you fat" we must have an understanding of how we gain fat in the first place.
When you eat food, the food is broken down and metabolized. We generally eat foods that are a mixture of the macronutrients that are fats, carbohydrates and proteins.

Fats and Carbohydrates are used for energy and protein is broken down into amino acids for our cells, for hormone production and for normal function. In the absence of carbohydrates, protein can be converted to carbohydrates through a process called glucogenesis. 

Carbohydrates are broken down into something called Glycogen and are stored for energy in the muscles. Excess glycogen is stored in the liver and this is where it is converted to fat for storage. Fats are stored in fat cells and are broken down into fatty acids and used for energy through enzymes. 

So, what happens to excess protein? This is where opinions, even very learned ones, differ and cross examining a few of these opinions I have drawn the following conclusions:

– Based on the fact that protein is absorbed and assimilated in the stomach and intestines by being broken down into amino acids and entering into the blood stream, excess amino acids are converted into Keto Acids and Urea by the Liver. This basically means that some of the excess amino acids are flushed from the body and some can be converted into glucose for energy

– The thermic effect of protein, in other words, the fact that protein requires more work from your metabolism to be absorbed and digested means that eating excess protein raises your metabolic rate thus, the extra calories eaten from eating too much protein are some what countered by this effect.

– Protein can be converted to fat and glucose but because of the above points, it is not the bodies priority to do so.

As for whether protein makes us fat or not, well we just need to look at a study conducted in 2012 by George Bray1 and his colleagues where they conducted a research experiment to see how levels of dietary protein affected body composition, weight gain and energy expenditure in subjects who were given three types of hyper caloric diets (in other words, they were given more calories than they required for maintenance)

All three groups were given 1000 calories above their 1400 maintenance calories (140% calories) for 8 weeks. Group A were the low protein group and would eat a diet consisting of 5% protein consisting of roughly 47 grams of protein. Group B were the normal protein group which consisted of 15% protein, roughly 140g of protein per day and Group C, the high protein group, consumed 25% protein which was about 230g of protein per day.

Carbohydrate intake was kept constant between the three groups at around 41-42% with dietary fat ranging from 33% in the high protein group to 44% and 52% in the normal and low protein groups respectively. After the 8 weeks of overfeeding, the subjects were examined for the results in their body composition using some of the most precise methods of measuring body fat (so, No Tanita scales were used that day).

The results showed that all subjects gained a near identical amount weight with close increases in body fat however, whilst the low protein group gained the least amount of weight (3.16kg), the normal and high protein groups, who gained 6.05kg and 6.51kg of weight respectively, actually gained LESS BODY FAT than the low protein group. What this means is that the excess protein contributed to a higher gain in lean muscle mass than the low protein group and whilst all of that weight may not have been lean body mass (some of the excess protein may have been converted to glycogen and stored in the muscles), it does show that the excess protein was not converted to fat allowing us to conclude that protein, even in excess, does not really contribute to significant fat gain. Of course, it would be interesting to see what would happen if the caloric intake was even higher with only protein being the variable factor changing.

So what about whey protein?

We've established what whey protein is and what happens to protein when it goes into the body. We've also seen that excess protein has the potential to be stored as fat but due to the pathway to do this, it is a very limited potential. Now, back to the epic question that started this whole blog article of in the first place. Does whey protein make you fat? Based on the science of what we've discussed above, whey protein has no reason to make you fat when compared to other types of protein in fact, research showed very little difference between whey protein and rice protein when body composition, performance and recovery were tested. 2

Whey protein, due to being derived from dairy, does not come without some cause for concern however. In individuals with dairy intolerance it can cause bloating, discomfort, flatulence and other symptoms of dairy intolerance in those who suffer from it. Good whey protein powders do come with added digestive enzymes to help with this but it is different from person to person. My suggestion would be to go with a brand that does put enzymes into their protein to make it more digestible such as the protein works or BSN. So, whilst whey protein won't make you fat on its own, it could be a cause for bloating and if that's the case, it may help to switch brands, supplement with digestive enzymes or take a powder with those in or to switch to a non whey protein powder such as hemp or brown rice protein. (I'm not a big fan of soy)

So what about excess protein and the kidneys? 

As for whether excess protein is harmful to the kidneys or not, I found the following from Dr John Berardi's site Precision nutrition 3 interesting:

"You might have heard the statement that a high protein intake harms the kidneys. This is a myth. In healthy people, normal protein intakes pose little to no health risk. Indeed, even a fairly high protein intake – up to 2.8 g/kg (1.2 g/lb) – does not seem to impair kidney status and renal function in people with healthy kidneys. In particular, plant proteins appear to be especially safe."

Of course, high protein diets have been a cause of concern to people with kidney damage or with a history of poor kidney health but there is nothing then to indicate that in healthy human beings, that excess protein will cause any strain in the kidneys. Yes, excess protein will force your kidneys to work harder to rid your body of metabolites from proteins but as stated, in healthy humans, this isn't a problem because your kidney's are geared for the job!

What about protein and calcium leeching then?

Okay, I am going off topic with regards to whether protein makes you fat or not but whilst we're debunking myths about protein, let's have a quick look at another oyster. Excess protein causes osteoporosis because of calcium leeching due to protein causing your body to become a more acidic environment which causes the body to take calcium from the bones to neutralize the acids however, it is safe to say that numerous studies have been conducted and none show any adverse effect to calcium in the body when the amount of protein was increased in test subjects.4

So, In conclusion, we can deduce that excess protein isn't evil and whey protein won't really make you fat. In fact, eating a diet high in protein and whey protein will have more positive effects than adverse ones including a raise in metabolic rate, lean muscle mass, cell recovery, satiety and other health factors. Of course, nothing should be done in excess and it is recommended that most people get around 0.8grams of protein per kg of body weight (although that is just the government guidelines) but a recommendation would be closer to 1% and 2% per kg of bodyweight in athletes and those with physically demanding lifestyles. Now, I don't know about you, but I could sure go for a steak right about now :)



1.  Bray GA, Smith SR, de Jonge L, Xie H, Rood J, Martin CK, Most M, Brock C, Mancuso S, Redman LM: Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial. JAMA 2012, 307:47-55.

2. The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance.  – Joy JM, Lowery RP, Wilson JM, Purpura M, De Souza EO, Wilson SM, Kalman DS, Dudeck JE, Jäger R.

3. Precision Nutrition –

4. Effect of Dietary Protein Supplements on Calcium Excretion in Healthy Older Men and Women – Bess Dawson-Hughes, Susan S. Harris, Helen Rasmussen, Lingyi Song, and Gerard E. Dallal

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