Protein supplements are popular and effective for building muscle strength and bulk, but can you have too much protein? Top 10 Supplement Reviews looks at the research to explain how much is too much, and what happens if you overdo it.
The key to using protein is understanding what it does for your body, so you can get the right amount at the right time.
What happens when you consume protein?
Protein supplements are designed to help your body build muscle tissue. They do this through a complicated process which boils down to a few well-understood facts.
When you do resistance exercise like lifting weights the tiny fibres in the muscles are damaged. As those fibres repair themselves, they grow back bigger and stronger, which is how your muscles grow. This is called muscle protein synthesis.
The body needs protein for this process to be effective, so protein supplements are designed to help your body build muscle.
What happens to the protein that isn’t used?
Protein is absorbed from your gut into your blood to be transported to the muscles. It will also pass through the major organs, including the liver, and any excess protein is eventually removed by the kidneys and passed out in your urine.
Research has found that a high-protein diet does not appear to harm the kidneys or liver, unless you already have damage or dysfunction in those organs. Some studies have found that rapidly increasing your protein intake might cause some liver or kidney problems, so take it slow if you want to add more protein to your post-workout shake.
Can I use too much protein if I’m trying to lose weight?
A study in 2016 brought great news for anyone who is trying to lose weight while retaining or gaining lean muscle mass. The research by a Canadian group found that overweight subjects were able to lose weight but still add lean muscle mass by using a protein supplement while cutting calorie intake and undertaking a rigorous exercise regime.
Urine tests also showed the kidneys were filtering out the by-products of muscle synthesis as expected, suggesting that any excess protein was also being removed effectively.
How much protein do you need?
In terms of daily protein, the amount you need varies depending on your lifestyle and body type. If you get very little exercise, then 1.2g per kilogram of body weight is probably enough, whereas someone who is more active and trying put on muscle mass may need as much as 3.3 g/kg.
You may also want to top up your regular diet with supplements after your workout, and scientific understanding in this area is constantly evolving.
For a while, the general consensus was that 20g of whey protein after a workout was the ideal amount to stimulate muscle protein synthesis; any more than that would simply be flushed out of the body.
That changed when a 2016 study led by the University of Stirling in Scotland found that its subjects responded better to a 40g dose of protein than 20g dose. The lesson from this is to keep abreast of developments in research, as new information changes what we understand about out bodies.
Can eating too much protein cause cancer?
You may see reporting which suggests studies have found that eating high levels of protein can cause cancer, but this is mostly sensationalism and you should always look a little deeper at the facts.
A common misunderstanding surrounds something called IGF-1, which is a hormone related to cell growth. You get a lot of it from protein, and it is key to your muscles to grow. Cancerous cells also use IGF-1 to grow, so there is a link between the two that can be confusing.
If you have a poor lifestyle and a diet with lots of low quality protein then the combination may lead to health problems, including cancer. If you are healthy and exercise regularly, then high levels protein are unlikely to be a problem.
What is the link between protein and diabetes?
If you have been diagnosed with diabetes then you need to be a little more cautious with your protein intake. Protein can be broken down into glucose, just like carbohydrates, but this process is slower for protein so the effects are not as immediate.
Kidney damage is a common complication of diabetes, and the kidneys are essential for processing protein, so if you have kidney problems you should consult your doctor before increasing your protein intake.
Research has found that some people with a high intake of red meat can be more at risk of developing type 2 diabetes, but the risk appears to be higher for processed red meat.
What should you do if you want to use more protein?
Before you decide to increase your protein intake, talk to your personal trainer to discuss your goals, exercise regime and diet to make sure you are eating as well as you can.
If you think you will benefit from taking on more protein, then it is generally recommended to consume more water when protein intake is being increased. The research on this is not clear, but good hydration is likely to help your kidneys and liver.
As a general rule, using too much protein will not cause you major problems if you are healthy and active and your protein sources are healthy ones. Be cautious if you have diabetes or any kidney-related health issues and, if in doubt, talk to your personal trainer or doctor for advice.