As always, this post is meant to be informative and educational and is not a prescription or recommendation for you as I cannot know your individual situation and needs. If you have concerns about your protein intake and want a specific recommendation, speak with a dietitian!
My goal in writing these blogs is to give you practical, easy to understand, not overwhelming nutrition information. Breaking down how to eat protein has been more difficult than I expected because there are so many different opinions about what the best amount of protein to eat is.
While this can be confusing and overwhelming, my takeaway for you is this: there is a wide range of protein intake that can be healthy. The amount of protein you eat can be flexible and for the most part can be adjusted to your preferences. (It is harder to get it wrong than a lot of people would like you to think it is.)
Two fast and easy ways to know how much protein to eat:
MyPlate is the U.S. Department of Agriculture’s recommended eating pattern. It isn’t perfect, but if about 1/4 of what you eat is protein food, you will most likely get enough protein – pretty easy to visualize if most of your meals are eaten on a plate.
If you only eat plant protein (vegans, and maybe some vegetarians), this still applies, but it is especially important for you to make sure you eat plenty of whole grains and vegetables as well. Keep reading here, but check out this post next.
Another super quick and easy method is to aim for about a palm-sized serving of protein foods with each meal. I like this method because it scales to the size of each person. A large person (who will need more protein) generally has a larger hand size. A tiny toddler (who needs less protein) has a tiny palm.
These two illustrations are also helpful because there is some research showing that eating your protein throughout the day (with each meal) is more beneficial than eating it all at once. (As your body uses protein throughout the day for many many purposes)
Now, as I said above, the amount of protein in a healthy diet can be very flexible, so you can eat more protein than this and totally still be healthy, as long as you aren’t excluding other necessary foods.
Do you like to do math and want to calculate the amount of protein you need? This section is for you.
(If you don’t like math, just skip to the next section 🙂 )
The minimum amount of protein required to prevent loss of lean body mass (muscle) in adults with no physical activity is generally calculated by dietitians as 0.8 grams of protein for every kilogram of body weight. (0.8g protein x kg of body weight). Factoring in a minimal amount of physical activity raises needs to about 1 gram per kilogram of body weight. In case you don’t feel like converting kilos to pounds, this works out to about 0.45g of protein per pound of body weight. If someone is critically ill, more active, or pregnant, this amount could increase, up to 2.0g/kg.
In terms of actual food, 1g per kg works out to about 1 oz of “meat equivalents” per 15 lbs of body weight. This is a rough estimate best suited to finding the base amount of protein you should eat. If you are concerned about your protein intake, or have questions, consult a dietitian! (I know I said it before – but it’s important! Also that’s what dietitians are here for!)
|1 oz “meat equivalent =
|1 oz meat, poultry or fish – about matchbox-sized
|About 7g protein=
|1 8-oz glass of cow milk or soy milk*
|1 oz cheese – about thumb sized
|1/2 cup beans or lentils
|1/4 cup or 1 oz nuts or seeds
|2 Tbsp peanut butter or other nut butter
|1/4 cup Greek yogurt or 1 cup regular yogurt (check the label)
|2 oz tofu
Whole grains and vegetables also contribute a small amount of protein (2-3g per serving)
There are some people who believe that everyone should eat more than this amount, and there are studies showing benefits of higher protein intake – such as improved muscle maintenance and function in older adults (1-1.2 g per kg body weight), improved satiety, and improved blood glucose control, among other things. Most people can eat up to 2g protein per kilogram of body weight without problems (those with chronic kidney disease would be an exception).
For some perspective, The Institute of Medicine recommends 10-35% of calories come from protein. For a 2000 calorie diet (which is the one used to calculate Nutrition Facts on labels), that is between 50 and 175 g of protein, or between 7 and 25 1-oz “meat equivalents”. Quite a large window. If 10-35% of your calories come from protein foods and you are above the 1g per kg minimum, you will probably be fine. Of course, (yes I’m going to say it again) if you have concerns, speak with a registered dietitian.
What happens if you don’t eat enough protein?
Too little protein intake results in a loss of lean body mass (muscle) because your body will break down the protein it is already carrying (muscle) to maintain its function. That’s why it is important that you are eating at least the minimum that your body needs. See this post for more information about how protein is used in your body.
Can you eat too much protein?
Yes. But if you don’t have a specific condition that would make it directly harmful, harm from eating too much protein is much more likely to be from two other causes:
1. Not eating enough from other food groups, like fruits, vegetables, and grains because of eating so much protein. This might mean missing out on important nutrients like vitamin C or fiber that come from those other food groups. This is especially likely when eating only animal protein foods.
2. Getting too much of the other nutrients that are often present in protein-rich foods. For example, cheese is high in saturated fat and sodium, which can be harmful for blood pressure and cholesterol levels. Many processed meats are very high in sodium and saturated fat as well. Again, this is more likely to be a concern with animal protein foods.
Extremely high protein intake can be harmful to the kidneys, however this is usually only in extremely high intake (like more than 2.0g/kg) over a long period of time. If you are getting most of your protein from foods, incorporating your other food groups, not taking excessive protein supplements, and don’t have any medical conditions, you are unlikely to be harmed by eating too much protein. Again, if you are concerned that you may be eating too much protein, consult a dietitian.
If you eat a lot of protein, will it make your muscles grow automatically?. No
If you aren’t exercising (or growing, or using steroids) to stimulate muscle growth, that extra protein will just be used for energy or stored as fat. See this post if you want more information about how this works.
Can you eat as much protein as you want without gaining weight? No
If you eat more protein than your body needs for its building and energy needs, it will still be converted to fat, just like any other food. See this post if you have more questions.
However, diets that allow unlimited protein (and limit carbohydrates or fats) have been shown to be helpful for weight loss. So why is this?
Protein tends to be more satisfying than carbohydrates or fats, so the thought is that eating more protein than other food groups makes you “full” faster and so limits the total amount you end up eating, resulting in weight loss.
So protein isn’t a magical weight loss food. But if it helps you eat less and still be satisfied, then it may help you lose weight (and as long as you are getting all the other nutrients you need, that’s fine).
What if I don’t eat meat? What about plant-based proteins?
Plant-based protein post coming next week! (I tried to fit it all in one post but it was too long!)
What other questions do you have about protein? Leave me a comment!
Resources if you would like to learn more:
- A good overview of protein, including protein requirements from Medical News Today: https://www.medicalnewstoday.com/articles/322825#recommended-intake
- A list of the protein contents of various foods: https://www.todaysdietitian.com/pdf/webinars/ProteinContentofFoods.pdf
- More protein content of foods of common food servings: https://www.vida.com/content/easy-protein-serving-sizes/
- Visual Guide to protein serving sizes: https://www.thekitchn.com/a-visual-guide-to-protein-serving-sizes-243496#comments-243496
- An article about protein in satiety and weight management: https://foodinsight.org/a-food-insight-series-on-the-power-of-protein-a-peek-at-protein-and-weight-management/
- A guide for clinicians discusses the increased need for protein in critical illness: https://nutritionguide.pcrm.org/nutritionguide/view/Nutrition_Guide_for_Clinicians/1342092/all/Macronutrients_in_Health_and_Disease#3
- A study from a publication from the Royal Society of Chemistry discussing protein recommendations: https://pubs.rsc.org/en/content/articlehtml/2016/fo/c5fo01530h
- A study in Advances in Nutrition: https://academic.oup.com/advances/article/8/2/266/4558082 . Do keep in mind that support was received from the beef industry for two of the authors. It does seem to be a fairly balanced and fair article, but keep that in mind.
- A contrasting perspective about the amount and source of protein: https://hilo.hawaii.edu/news/kekalahea/Misconceptions-protein