Are high potein diets safe, and how much is right for you?
This is a question I get asked frequently, often someone has read somewhere that eating protein is bad for the kidneys, is bad for your bones and will cause dehydration, yet they have also read an article that says the opposite, such as a high protein diet can actually help increase bone mass and is not harmful to the kidneys. Government guidelines suggest aiming for around 0.8 grams per kg of body weight, in my view this is insufficient for most people, so how much should you aim for and what levels are safe?
Do increased protein levels have negative side effects?
Research does suggest that high protein diets can be bad for the kidneys, yet this has only ever been demonstrated in an unhealthy kidney, of example someone with kidney disease. Recently studies though have demonstrated that eating 2.8grams of protein per 1kg of body weight has absolutely no impact on kidney function and in another study of similar protein levels kidney function actually appeared improved.
Research has shown increases in calcium and phosphorous loss on a high protein diet, which led some to conclude that bone health may be affected. Yet when you look at the study calcium intake and phosphorous were both limited in the study. This would not happen if your protein is mostly coming from whole food sources as it should as these are great sources of both calcium and phosphorous. Therefore as whole food protein levels increase so do those minerals, thus not effecting bone health. This is now backed up with numerous research papers demonstrating adverse effect on bone health.
Protein can lead to increased water loss, however so does exercise, does that mean exercise is bad for us, NO, it just means you need to drink more water. This is often a common problem with those that start to increase protein levels they start to experience constipation and sometimes headaches, typical dehydration symptoms. The addition of an extra litre of water and some extra vegetables usually solves the problem.
How much protein is right for you?
This is very individual and often best worked out on a gram per kilogram of body weight scale. This will then vary dependant on your goal. Is it muscle gain, fat loss, weight loss, muscle loss?
I have been told numerous figures as a protein goal, some over 4grams per kg of body weight, so for me that would be around 320grams of protein. If I were to achieve that protein goal with just whole food protein, that would equate to around 1.2-1.5kg of animal protein per day. I have tried this and found that it is not sustainable for me and very few of my clients and have also found little difference in results between 3grams per kg and 4 grams per kg of bodyweight.
Most of the research would suggest a protein goal of around 2.5-3grams per kg of body weight is sufficient for gaining mass. Essentially gaining mass is much more down to manipulation of the anabolic hormones such as insulin, testosterone and growth hormone whilst controlling the catabolic hormones such as cortisol.
Great fat loss results are usually achieved early doors by using a higher protein diet with lower carbohydrates to help control and limit the amount of insulin being excreted. Whilst this can be helpful short term my belief is that staying on high protein and very low carb diets can be harmful in the long term by negatively impacting our ability to use carbs on a cellular level and possibly affect metabolic function by affecting thyroid function. Whilst these may not be immediate I now rarely go over 4 weeks very low carb with my clients before I start cycling in increased level of carbs. At that point I may lower protein levels slightly as the additional calories will be coming in from carbohydrates.
1.5-3grams per kg of body weight is usually sufficient, during a fat loss phase.
Muscle loss protocols are not ones I enjoy writing for clients yet some of the clients I work with have to be in a specific shape for a film role that may require dropping some lean tissue. Protein levels would then have to be dropped below 1g per kg of body weight and overall calorie levels would have to be dropped low with a combination of steady state cardiovascular training.
Staying on a diet like this can certainly be harmful and I see the effects of this type of dieting on metabolism in yo yo dieting and low calorie dieting Individuals, mostly females. Often a phase of metabolic recovery is required to start to attain optimal health and long term fat loss.
My approach with clients that desire muscle loss is always, get the fat off first then concern yourself with the muscle, usually once the body fat levels are down no muscle mass is required to be lost.