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What Happens If You Only Ate Protein?

Updated: Sep 26, 2020

Protein is an essential macro-nutrient for your general health and well-begin. It's used to build muscle and to make other proteins that are essential for the body to function. It's benefits include increased performance and quicker muscle recovery. But what happens if you only eat protein?

If we consider the NHS who state that a woman's daily protein intake should be 45 grams and 55.5 grams for men, this would be more than doubled. For example, if you're a woman and you consume 2000 calories worth of chicken breast, you would be getting 1.2kg of chicken. This is 378.2 grams of protein; over eight times a female's recommended intake and almost seven times a male's recommended protein consumption. Therefore, there would be serious implications to eating this much. The NHS recommend that bodybuilders and those who need more protein do not surpass double the recommended intake.

If we look into the effects that excessive protein intake had on various studies, these were some of the implications involved.


Eating nothing but protein will send a person's body into a state ketosis. This name may register with you as ketosis is what the famous keto-diet achieves. Ketosis is essentially when you eat less than 50 grams of carbs per day and due to this lack of carbs, your body is unable to attain energy from carbs as it usually would. It then goes to fats for energy instead.

However, ketosis has a secret negative effect on a person's breath that nobody ever discusses. This happens due to the chemicals that ketosis produces which gives a person's breath an unpleasant fruity smell. So stock up on those breath mints if you are considering this type of diet.


If somebody was to eat nothing but protein, they would not be eating their five a day (fruit and vegetables). These are the foods, along with grains, that contain the highest amounts of fibre and the NHS recommends that an adult gets 30 grams of fibre a day. Fibre is linked with a lower risk of heart disease, stroke, type 2 diabetes and bowel cancer. However, it is also important for helping with bowel movements. Therefore, if a person was only eating protein, without fibre, they would likely become constipated.

To help with this, plant proteins are a great hack as, unlike meat, they are high in fibre. This is a reason why plant-based proteins can be very good if you are trying to increase your protein intake but also maintain essential levels of fibre in your diet. For example, A KIND protein bar contains lots of fibre due to the nuts contained in a bar, while also providing your body with 12 grams of protein. This may not be as much as a scoop of whey protein powder or a chicken fillet but it's a great way to get some healthy carbs in.


The lack of fibre can also go in the opposite direction and cause diarrhea. This is due to consuming too many processed foods or having a diet with too much dairy. Too much dairy would cause diarrhoea as a person's body would not be able to product enough enzymes to break down the milk sugar in time, leaving it indigestible and thus, the body gets rid of it fast.

There are, of course, health benefits to dairy though as it helps brain growth, bone density, skin health and digestive system functionality. But anything above moderation could cause diarrhoea, so drink responsibly.


One study carried out in 2012 found that eating too much red meat can be linked to an increased cancer risk! However, eating other types of meat, such as chicken and fish actually decreased the risk of cancer. So, a person who was only eating protein would find that they need to vary the protein types to avoid this risk.

Plus, eating lots of red meat and full-fat dairy foods can also lead to heart disease due to the high fat and cholesterol content. Therefore, red meat, like anything, should be consumed in moderation.


In summary, if you only ate protein, you would defiantly see some benefits, such as the usual increased performance, increased lean muscle mass and decreased ageing of muscles in older people (the fill list of benefits can be seen in the blog post 'Why is Protein Funadmental' on the blog page of the MEANPROTEIN website).

However, the cons would outweigh the benefits in this extreme situation. You may end up with bad breath, constipated, with occasional diarrhoea and with the possibility of cancer if you eat too much of certain proteins.

Therefore, it is healthy to maintain a balanced diet with the correct amounts of protein, carbs and fats in order for your body to thrive.

If you are looking to increase your protein intake, why not try a MEANPROTEIN protein subscription box which contain a healthy range of whey protein, protein bars and snacks.This way, you won't be going crazy eating 378.2 grams worth of chicken breast but instead, you will be balancing your diet with carbs and fats too. Plus, there's nothing better for a diet than having some healthy snacks around. Check out the two boxes on the MEANPROTEIN shop page.

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