The Surprising Downsides of Consuming Too Much Protein

Lately everyone seems to be talking about how good protein is for us, especially as we age.  You have probably heard things like:

• As you age, you should increase your protein intake to conserve muscle mass
• Eating more protein helps you increase strength, muscle mass and bone density
• Eat more protein to reduce food craving and lose weight (think, the Atkins diet)
• It is important to eat a lot of protein after surgery or injuring yourself so your body can adequately repair itself.

Wow!!! Protein seems to be the stuff of miracles!!!

And while I totally agree that protein is pretty amazing stuff, I also want to highlight that there are some surprising negative effects of eating too much protein too, especially if you are interested in increasing your health span and avoiding debilitating chronic illnesses like obesity, heart disease, diabetes.

Prefer watching to reading?   Click here to see my Youtube video on this topic

In this article my goal is to empower you with information you need so you can decide how much protein and which type of protein to consume according to your personal goals.

But first, let’s start with some protein basics…….

• • • Most scientists agree that our body needs us to consume about 0.8 grams of protein per kilogram of lean body weight each day (or .36 grams per pound) to replenish the protein we lose each day.  That means that if your ideal body weight is 65 Kg (143 pounds), then you should consume about 52 grams of protein per day.
    • Protein mainly comes from the following foods (in order of the amount of protein they contain): animal and dairy products, pulses (beans, lentils, chickpeas etc), nuts, seed and grains. 
    • No foods are 100% protein.  All foods also include various amounts of carbs or fat, water, fiber and micronutrients (vitamins and minerals etc).   Let’s use a 100% beef patty as an example.  While the patty may weigh 100 grams (about 4 ounces) it actually only contains about 20 grams of protein.   The rest is mainly fat and water.    So to get all your 52 grams of daily protein from hamburger patties you would have to eat about 250 grams of them ( half a pound).
    • As a general rule of thumb, animal and dairy proteins contain “protein mixed with fat” whereas vegetable proteins contain “protein mixed with carbs”.
    • Also, animal proteins are considered “complete proteins” because they contain all of the 9 essential amino acids in the quantities our body needs, whereas vegetable proteins are generally considered “incomplete proteins” because they often lack sufficient amounts of specific essential amino acids.   Thus it is generally recommended that vegetable protein be combined with other foods so that our bodies can properly utilize the protein they contain (for example eating beans with rice).

Is your goal to build as much muscle as possible?

If your goal is to build as much muscle as possible as quickly as possible, then the science shows that increasing your protein (and carbohydrate) intake is going to help you do that, provided you are challenging your body sufficiently in your strength training sessions.  Many doctors and scientists recommend consuming twice or even three times as much protein as the basic requirements if you want to increase your muscle mass.

Is your goal to be as healthy as possible and increase your lifespan/ healthspan?

If your goal is longevity and reducing your chances of getting a nasty chronic illness like cancer, heart disease, diabetes etc (or reversing these conditions if you already have them),  then eating more protein may not be the best option for you.

In 2012 scientists in New Zealand and Australia published studies showing that the restriction of proteins in the diet increases lifespan and suppresses the incidence of age-related disease (see links to the studies here and here).   This is because increased protein intake activates “mTOR” which is a substance in the body that has been implicated in many of the processes that are associated with aging.

Basically the equation works like this:   More protein = more mTOR activation = faster aging = more chronic disease.   

So while more protein will probably help you conserve and maybe even build more muscle as you age 😊 , it comes with the cost of making you age faster 😕.  

So if your goal is health and longevity you would be wise to limit your daily protein intake to the mínimum 0.8 g / kg amount that I mentioned above.

The type of protein that you consume is also crucial

Not all proteins are equal.  Each source of protein (for example, beef, beans, quinoa, cheese etc) contains a different ratio of amino acids and this is important because:  

A new study published in 2021 in Japan by a scientist named Munehiro Kitada and his colleagues showed that the restriction of a specific amino acid in protein called “methionine” is principally what benefits lifespan extension and metabolic health.  

So what proteins are high in Methionine?  

The proteins that are highest in Methionine are meat and fish in general (especially turkey, beef, pork and tuna) and BRAZIL NUTS.

So what proteins are low in Methionine?  

The protein foods that are low in Methionine but still contain ALL the other essential amino acids required by our body are: Pulses in general (beans, chickpeas and lentils etc) and walnuts and hazelnuts.

The above diagram compares the essential amino acid requirements of our bodies (in blue) with the essential amino acid profile of lentils (in red).  As you can see, lentils closely match the requirements of our bodies except with regard to methionine (circled in yellow)

Should I try to eliminate foods high in Methionine from my diet?

You could, but it is not necessary to.  Just eat them less frequently.   

For example if you currently eat meat or fish and dairy products everyday, my suggestion is to cut back to about about 3 times a week and on the other days consume proteins that are low in Methionine like lentils (think “lentil soup with mushrooms”), beans (think a “hearty minestrone soup”) and chickpeas (think “humus”, yum).

Make sure you remember this!!

Consuming some methionine is crucial for normal health.

In moderate quantities, Methionine has positive effects on the body such as helping to process fats and reduce cholesterol levels, preventing kidney stones, reducing the damage from heavy metals in the blood, counteracting the toxic effects of acetaminophen (Dolex), helping to prevent hair loss and graying, and strengthening nails.  

Remember, Methionine is an essential amino acid so you definitely don’t want to eliminate it completely, as could happen if you eat a poorly balanced vegetarian diet.  

A deficiency of methionine can lead to inflammation of the liver, anemia, and graying hair. 

My recommendations

• • • • Consider reducing your consumption of meat, fish and dairy products.   If you currently eat these foods everyday, multiple times a day, aim to eat them just once a day.  On the other hand, if you currently eat these foods just once a day, cut back to once every two days (3 – 4 times a week in total). Remember to still eat protein on the days that you are avoiding meat, just choose a vegetable source.
      • Don’t become a vegetarian.  Yes really!!!!  Becoming a vegetarian may sound like the perfect solution, because a vegetarian diet is generally low in Methionine (with the exception of Brazil nuts), however unless you are super committed to learning about nutrition and getting your blood work done regularly to make sure you are not deficient in anything, it is very easy to make your health worse by completely eliminating animal and dairy products from your diet.   The sweet spot seems to be consuming meat and or dairy products about 3 times a week for maximum health.  If you are determined to become a vegetarian and would like some help making the transition, I can certainly help you with that.   Check out my coaching program.
      • Make sure you are doing some sort of strength training.    Just eating more protein won’t help conserve or build your muscle mass.  The most important tool for building/conserving muscle and bone density is doing some form of strength training 2-3 times a week.   A study published in JAMA internal medicine found that eating more than 0.8 grams of protein had NO significant effect on helping older men build muscle.   Remember, strength training does not mean that you have to lift weights in the gym.   The body weight exercises in some types of yoga (such as Power Yoga) are also great strength training too (for example warrior pose, plank pose, twisted chair pose and down dog pose)  
      • Discover how much protein you actually eat.   Most of us have no idea how much protein we really eat and it is often way more or less than you think.   This is why I suggest that you track your protein intake over a week to get a sense of how much protein you normally consume and make some adjustments if needed. When I did this I realized that I was eating way less protein than I originally thought.  Tracking your protein intake is a little bit tedious and will require you to weigh your food and read all the labels on the packages you eat, but remember it’s only for a week and what you learn will definitely make it worth the effort.