High protein diets have been popular for years now as people have come to realise the important role this macronutrient plays in health and fitness. However, there are a number of myths surrounding protein intake – specifically the health effects of a long-term high protein diet – that we want to discuss in today’s post.

Kidney Damage

“High protein diets damage your kidneys.” This myth derives from the filtering process that the kidneys are responsible for in the body as they remove toxins and waste from the food and drink we consume. The digestion of protein requires the kidneys to work harder to remove these natural by-products, but for normal healthy people, this isn’t a problem. The capacity of the human body should never be underestimated. In those who suffer from kidney disease, the long-term consumption of a high protein diet can strain the kidneys and lead to a build-up of waste product in the body, which is obviously bad news. If you suffer from kidney problems, talk to your doctor about your protein intake and also look at your protein sources. Choosing plant-based ones over animal will lessen the pressure on your digestive system and help to safely maintain an adequate protein intake.


“You can only absorb 30g of protein in one sitting, the rest passes through undigested.” This popular myth is, unfortunately, untrue. There’s no cap on the amount of energy we can extract from food in a single sitting. Otherwise, instead of counting calories to lose weight, we’d switch to an all protein diet! The grain of truth in this myth is that protein digestion is the most energy-intensive of all the macronutrients – 20-30% of its contained energy is used, as compared to 5-10% for carbs and 0-3% for fats. Therefore, a diet that’s high in protein will lead to a lower calorie yield after digestion. This is why it’s important to examine the nutrients behind the calorie count when planning your meals, especially if your goal is to lose weight.

Bone Health

“A high protein diet can cause osteoporosis.” This myth requires a mini science lesson to explain (bear with us it won’t be complicated). The protein contains amino acids. There are 21 in total, 9 of which are ‘essential amino acids’ because they must be taken in through food. The other 12 can be made by the body using the essential 9 (the body is marvellous, isn’t it?). Amino acids are used to build and maintain muscle mass. The myth posed above is based on the incorrect assertion that the body, when overloaded with acid, will use the calcium in the bones as a neutraliser. This isn’t true. In fact, having a healthy muscle mass is one of the most powerful weapons in the fight against osteoporosis because it supports proper load-bearing and builds bone strength. In other words, bones work to support the weight of muscle and this makes them tough and resilient to damage. The same is not true for fat because of the difference in distribution (i.e. the way fat hangs on the body).

Don’t Believe Everything

While today’s blog has debunked three of the most common protein myths, there are plenty more out there that we haven’t covered. Our advice is to not take everything at face value and to do a little investigation before accepting something as true. Be wary of social media celebrities too – they often build a brand on their personalities or lifestyle, not on education or knowledge. If after some research you’re still unsure, turn to a professional such as a personal trainer, a dietician, nutritionist or even your doctor.

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