How Much Protein Do You Need? ALL Your Questions Answered with A Registered Dietitian

Protein has been a hot topic in nutrition for the last few years, and the hype doesn't look like it will die down anytime soon.

Yet, most people still don't know how much protein they need. This article will hopefully help change that.

Protein is one of the three macronutrients. It plays a structural role in our body, forming blood cells, skin, hair, nails, hormones, enzymes and more. Without protein, our body would be unable to build the tissues we need to survive. 

In this post, we’ll discuss the role of protein, protein intake recommendations for weight loss and muscle growth, plant-based diets, protein timing, and more in-depth.

Why Is Protein Important?

1. Protein is an energy source, just like carbohydrates and fat, providing calories/energy for our body to function.
2. Proteins are necessary for the proper functioning of the cells our body is made up of. We cannot live without them.
3. Protein is a bit like the scaffolding of our cell body, giving us shape and keeping us upright.
4. Protein is needed for growth, repair, and healing in our body.
5. Proteins create hormones. Hormones carry important messages between cells, tissues, and organs in the body and help coordinate bodily functions.
6. Enzymes are proteins. They carry out important chemical reactions in the body, like digesting nutrients.
7. Antibodies are vital proteins that keep our immune system working well to fight diseases and infections.

The RDA For Protein

The US RDA (recommended dietary allowance) for protein is a very conservative 0.8g per kg of body weight per day. However, the RDA for protein is just the bare minimum you need to eat to avoid protein deficiency. Many studies have shown that even sedentary people would benefit from eating more protein daily.

Protein Metabolism

Now, the first thing I need you to know about protein is that, unlike fats and carbs, we cannot store protein in the body, which means that we must consume a sufficient amount of protein each day from food. Carbohydrates and fat can be stored until they are needed. But your body is constantly breaking down and rebuilding new protein and muscle. This is called ‘protein turnover’. It's an energy-using process, and this is why people with more muscle have higher metabolisms.

How Much Protein Do You Need?

Protein Requirements For General Health

Sedentary Adults

Well, as I mentioned, the RDA is 0.8g/kg of body weight/day. So, if you do the math, this means an 80kg human will need 64g of protein. However, this is the bare minimum!

If you don't know your weight in kg, take your weight in lbs and divide it by 2.2.

For most of my clients, I typically advocate aiming for at least 1-1.2g of protein per kilogram of body weight per day. So, if you weigh 80kg, you ideally want to have at least 80g of protein a day as a good benchmark.

Active Adults

Now, for active people looking to build or even maintain muscle, the International Society of Sports Nutrition (ISSN) recommends that we should eat 1.4 to 2.0 grams of protein per kilogram of body weight. If you’re keeping score, that would be 112 to 160 grams of protein per day for a person weighing 80kg.

Protein Requirements For Weight Loss

If you are trying to lose weight, you are likely to be eating in a calorie deficit. In this scenario, you want to minimise losing muscle mass (which can be hard when you are not eating as much) and focus on primarily losing fat mass. So, to avoid this, you may need even higher protein intakes again.

Some research suggests that higher protein intakes above two grams may be beneficial in the context of weight loss in that they can support the maintenance of muscle mass whilst losing fat mass. However, it's important to remember that consuming more protein than you need doesn't offer an advantage in terms of health or physical performance. And if you're trying to lose weight, overeating on any macronutrient will not be helpful.

But generally, in weight loss, the higher your energy deficit, the more protein is recommended. A high protein intake is also really helpful if you are trying to lose weight because Protein decreases appetite by reducing our hunger hormone and increasing our satiety hormone.

Protein Requirements For Muscle Gain

More protein does not always equal more gains. 

In one particular study, strength athletes were assigned to either a 

• low protein diet providing 0.86g per kilogram of body weight per day, 
• a moderate protein diet providing 1.4g and 
• a high protein diet providing 2.3 grams.

The low-protein diet group had muscle mass loss after the intervention. However, both the moderate and high protein diets resulted in an increase in muscle mass. However, the increase was the same among both groups, indicating that no further benefits were actually gained from increasing protein intake from 1.4 grams to 2.3 grams per kilogram of body weight. However, if you are on a bulk and you decide to reach for the upper intake of protein, whilst it isn’t likely to help you build more muscle, it can help you minimize the fat gains you’ll most likely experience if you eat above maintenance calories in order to gain weight.

A HUGE mistake people make is focusing on protein without looking at other aspects of their nutrition, such as overall energy and carbohydrate intake. Protein has a “sparing effect”, which means that when insufficient amounts of energy or carbohydrates are consumed, protein can be used to provide energy instead. However, this means that its usual functions, such as the maintenance of hair, skin and nails, and muscle repair and growth are restricted. So, whilst protein is important, overall energy and carbohydrate intake is just as important to ensure the protein can be used for what it is designed to do. 

Of course, the other really important consideration is that if your goal is muscle gain, you actually need to go to the gym and use those muscles. Simply drinking protein shakes on their own won’t do the trick. Resistance training, such as lifting weights, is, of course, required for muscle gain.

Now, all that said, nutrition is never a one-size-fits-all approach. Protein intake is individual and depends on several factors, including your age, weight, activity level, and goals. Your protein requirements will also change throughout your life. For example, women might need to adjust their protein intake during pregnancy and lactation to keep up with their body’s needs. People over 65 may also need to increase their protein intake since the body uses protein less efficiently as we age. So it starts to get harder to keep rebuilding up that muscle.

Protein Timing

You may have heard that your body can only absorb a certain amount of protein in one sitting. While this is not directly true, there is evidence that spreading out your intake across the day rather than having large amounts of protein in one or two sittings is better for muscle growth. 

The International Society of Sports Nutrition recommends that regular doses of 20 to 40 grams of protein every three to four hours are most beneficial for muscle protein synthesis. Or, if you want this more specific to you, you want to eat 0.25g to 0.4g of protein per kg every 3 to 4 hours. The older you are, the more protein you should aim to have at each sitting.

But again, meeting your total daily protein intake is the first priority; then if you can, trying to spread this out to every three to four hours has been shown to improve body composition and performance in individuals who exercise. What I tend to see in clinic with clients is that most people eat the bulk of their daily protein intake at dinner, which might not be a great strategy for building muscle.

Protein Quality

Amino Acid Content

When we talk about the quality of protein, dietitians usually refer to the amount of essential amino acids (AAs) they provide and how well our bodies can digest and use the protein. 

There are 9 AA’s that are considered essential. Essential means that we cannot make them within our body and so it is essential that they are obtained from food. Generally speaking, the protein we get from animal-based sources like meat, fish, eggs and dairy are considered complete sources of protein, meaning that they contain all nine of the essential amino acids that our body needs. 

Plant-based protein sources, such as beans and lentils, typically lack an essential amino acid or have lower levels of amino acids. 

However, there are some exceptions. Soy-based protein sources like soy protein isolate, soy milk, yogurts, tofu, and tempeh contain all nine essential amino acids. 

You can also combine different sources of plant-based protein at a meal to compensate for the missing amino acids. These are called complementary proteins. For example, Beans are high in lysine but low in methionine, whereas bread is low in lysine and higher in methionine. Combining beans with toast makes a meal that can provide all essential amino acids.

Leucine Content

Now, one amino acid of particular importance is leucine, which plays a key role in stimulating muscle protein synthesis. It's like a trigger for the muscle-building process.

Research shows that 2.5-3 grams of leucine are needed to stimulate muscle growth; this is known as the "leucine threshold."

It's much harder to reach this threshold with plant over animal proteins. 

To crunch the numbers, one typical (3.5-ounce or 100g) serving of chicken breast contains 2.3 grams of leucine. To reach this same threshold, you would need to eat 5.3 ounces or 150g (about 2.5 servings) of lentils.

The same goes for protein powders. In whey protein, leucine is about 12%, so 23 grams of whey protein isolate will trigger the 2.5 leucine threshold, whereas in soy protein isolate, it's about 7.8%, so now you need 33 or 34 grams to trigger this threshold.

Bioavailability:

A final thing to consider when it comes to protein type is bioavailability.

Bioavailability refers to the amount of a nutrient that we can actually absorb after it is eaten. Quite often, plant-based proteins are harder to digest because they contain fibre, but also because they may contain phytates, which can decrease the absorbability of amino acids. The American College of Sports Medicine advises that vegetarian athletes need to eat around 10% more protein than if they were not vegetarian to accommodate for the lower levels of essential amino acids in plant foods, but also due to the bioavailability of amino acids found in these.

Now, don't let the above turn you off plant proteins. All of the other nutrients they provide, like fibre, vitamins, and minerals, still make them an excellent option.

Frequently Asked Question

How To Eat More Protein

I believe it’s easier than you think to eat 100 grams of protein daily. Here are some of my top tips and swaps for working more protein into your diet:

1. Aim to eat every three to four hours and include a protein-rich food with each meal and snack.
2. Always start your day with a good protein source; this is especially important after an overnight fast, so protein at breakfast should not be overlooked. 
3. Swap white rice for quinoa to get almost double the protein. 
4. Use Greek yoghurt instead of traditional yoghurt to get twice the protein.  
5. Consider cooking protein in bulk to have it readily available throughout the week. Always have some boiled eggs in the fridge and cook a few chicken breasts at a time,
6. For quick meals or snacks, stock up on pre-prepped or pre-cooked protein (canned tuna, Greek yoghurt, rotisserie chicken, protein powder, etc.). 
7. Swap traditional pasta for a bean or lentil-based alternative such as chickpea pasta to get an extra protein boost. 
8. Stock up on carbs that double as good protein sources (beans, lentils, chickpeas, etc.).
9. Add hemp seeds or chia seeds to oatmeal or yoghurt. Three tablespoons of hemp seeds provide nearly 10 grams of protein.
10. Use bone broth as a base for soups or to cook rice.
11. Use plain Greek yoghurt instead of sour cream in recipes. 
12. Sprinkle nuts and seeds on other foods or eat a handful as a snack. 
13. Add beans or lentils to soups or pasta dishes. 
14. Add peas to meals. One cup provides eight grams of protein. 
15. Add protein powder to oats, pancakes or baked goods. 
16. Use nutritional yeast for a plant-based cheesy flavour. Two tablespoons provide five grams of protein. 
17. If cost is a barrier, mycoproteins such as “Quorn” are much cheaper protein alternatives made from fungi. TOFU is also much cheaper than many meats and can be absolutely delicious if cooked right

This post was all about how much protein you need based on your individual goals. If you enjoyed this article, I would recommend reading my post about creatine supplements next,

Connect with Maria Lucey, RD!

Don’t forget to follow me on Instagram, YouTube, and Pinterest so you never miss a new recipe or blog post.

Recipes You May Enjoy:

• 💫The Original Baileys Cheesecake Recipe – Irish Cream No-Bake Cheesecake
• 💫Almond Butter Energy Balls Recipe

More about the author:

Hi there! My name is Maria, and I am a Registered Dietitian practising in Ireland and Bermuda. I have extensive experience in helping clients improve their health through the power of good nutrition. I hope you enjoyed this article. If you have any questions or concerns, please do not hesitate to contact me. Additionally, if there are nutrition topics or recipes you would like me to make in future posts, please let me know. I would be more than happy to help.

Stay happy and healthy 💚

Your Registered Dietitian

Maria xox

Check me out on YouTube!

🎥 Visit my YouTube Channel to learn more about my approach to eating and see many of my healthy recipes.