How much protein do I need? A dietitian answers

How much protein do I need?

Your protein needs depend on factors including your age, activity level, height and weight.

In general, healthy adults can use the following formulas to calculate protein intake.

Ages 18 to 65

Generally, adults ages 18 to 65 should eat 0.8 grams of protein per kilogram of body weight.

Weight (in kilograms) x 0.8 grams = grams of protein per day

For example, a 40-year-old person weighing 180 pounds would convert their weight to 82 kilograms and multiply by 0.8 to get 65 grams of protein per day.

Ages 65 and older

Adults aged 65 and older should eat 1 to 1.2 grams of protein per kilogram of body weight to prevent weight loss.

Weight (in kilograms) x 1.0 to 1.2 grams = grams of protein per day

Active individuals

Athletes and very active individuals may need even more protein: up to 1.2 to 1.5 grams per kilogram of body weight.

Weight (in kilograms) x 1.2 to 1.5 grams = grams of protein per day

Individuals with health issues

Your medical history can also impact your protein needs.

For example, you will need more protein if you:

• Are undergoing cancer treatment
• Have diabetes
• Are on dialysis
• Are pregnant or postpartum

You should consume less protein if you have chronic kidney disease but aren’t receiving dialysis.

A dietitian or other health care provider can help you calculate your protein intake based on your health history.

What foods are good sources of protein?

Dietary protein can come from animal-based or plant-based sources. Here are some examples of each and how much protein a healthy portion contains.

Remember: a portion looks different for each food. For example:

• A healthy portion of meat is 3 ounces, or about the size of a deck of cards.
• A healthy portion of cheese is one ounce, or about the size of 4 small dice.
• A healthy portion of nut butter is 2 tablespoons, or about the size of a golf ball.
• A healthy portion of beans is one cup, or about the size of a baseball.

Animal-based protein

Dairy products, eggs, fish, poultry and red meat are good sources of animal-based proteins.

• Beef, 3 ounces – 27 grams
• Chicken breast, 3 ounces – 26 grams
• Eggs, 3 medium – 21 grams
• Tuna, 5-ounce can – 20 grams
• Salmon, 3 ounces – about 17 grams
• Cottage cheese, ½ cup – 14 grams
• Ricotta cheese, ½ cup – 14 grams
• Protein powder, 1 scoop – 14 to 20 grams
• Greek yogurt, ½ cup – 10 to 16 grams
• Milk, 1 cup – 8 grams
• Cheese, most types, 1 ounce – 7 grams

Plant-based protein

Beans, lentils, nuts and seeds, whole grains and soy products are good sources of plant-based protein.

• Lentils, 1 cup – 18 grams
• Beans, 1 cup - 16 grams
• Peanuts, 2 ounces – 14 grams
• Soy milk, 1 cup – 8 grams
• Soy products, ½ cup – 7 to 16 grams
  
• Nut butter, 2 tablespoons – 7 grams

What’s better: animal protein or plant protein?

The short answer? Both options are good sources of protein.

Want to know more? Here are some differences to consider.

Animal proteins are complete proteins. This means they contain each of the nine essential amino acids. Not all plant-based proteins are complete proteins. However, you can still meet your protein goals on a vegan or vegetarian diet: simply eat a variety of plant-based proteins each day. This way, you will get all the essential amino acids your body needs — they don’t need to be consumed at the same time to work!

Animal proteins are easier to digest than plant-based proteins. They also have fewer anti-nutrients, like lectins, which can impact your body’s ability to absorb protein. However, animal-based proteins can have a larger environmental impact than plant-based proteins.

Another plant-based protein pro? They have nutrients, like fiber, that animal proteins don’t have or contain less of.

What happens if I don’t get enough protein?

If you don’t get enough protein in your diet, it can prevent your body from working its best. One common example of how? Muscle weakness and loss. You may also notice skin and hair health changes, blood sugar imbalances and a weakened immune system.

Most of these signs don’t appear overnight. For example, weakness or muscle loss may take weeks or months to show up. These changes may be noticeable sooner in athletes and older adults.

There isn’t a blood test or nutrition indicator that is used to tell if you are getting enough protein. While you may have heard of blood tests called protein labs, those don't always reflect oral protein intake. Instead, health care providers can determine if you are getting enough protein by considering your muscle mass and diet.

Is it possible to consume too much protein?

Eating too much protein isn’t really a concern for most people. This is because your body gets rid of any extra protein you consume. However, if you have kidney problems, you may have decreased protein needs because the kidneys help your body excrete protein.

When choosing a protein source, remember that options like red meat, processed meat and full-fat dairy products can be high in saturated fat.

Does cancer affect protein needs?

Yes. If you have cancer or are immunocompromised, you need more protein and nutrients. Consuming enough protein during cancer treatment prevents weight and muscle loss and supports the immune system. If you are recovering from surgery, your protein needs may also increase to support wound healing.

For cancer patients, not getting enough protein can weaken the immune system, increasing the risk of malnutrition. It can also lead to muscle loss, which weakens your body and makes it harder to do regular daily activities.

Protein needs during cancer treatment can range from 1.2 to 2 grams of protein per kilogram of body weight. This is calculated based on your age, weight, cancer type and other health history.

It can be hard to meet your nutritional needs when you’re not feeling well or have side effects like nausea. If you're an MD Anderson patient, you can ask for a referral to an MD Anderson clinical dietitian who can work with you to personalize your calorie, protein and fluid needs.

Is it OK to get protein from protein powders or shakes?

While I always recommend getting nutrients from whole foods first, that isn’t always realistic. Maybe you don't have an appetite or are simply too busy to sit down for three balanced meals a day. In those cases, protein shakes and powders can help you meet your nutritional needs.

Protein shakes and powders can also help you get enough protein when cancer treatment and symptoms affect your ability to eat. They are already broken down compared to protein sources like chicken or beef. This makes them easier to digest.

Here’s how to choose the product that’s right for you.

Learn the types of protein powder

Here’s a quick look at the types of protein powder available.

Whey: This protein is created from the liquid that forms when cheese is made. It is digested quickly. It is a popular choice for people who want to promote muscle recovery and growth after a workout.

Within the whey family, there are whey protein isolate and whey protein concentrate. Whey protein isolate has more protein and fewer carbs and fat than whey protein concentrate. It is safe for people who are lactose intolerant. Whey protein concentrate has less protein than whey, but more carbs and fat.

Casein: This milk-based protein is digested slowly and can keep you feeling full for longer.

Plant-based: Protein powders that don’t contain animal products can be made from ingredients like peas, soy, hemp, egg whites or brown rice.

Understand your goals

Protein powders and shakes can vary in calorie and protein content. Check a product’s Nutritional Facts label to learn how many calories and grams of protein a serving has. Generally, protein powders have about 20 to 30 grams of protein per serving, while protein shakes can include up to 40 or more grams per serving.

If you're making a smoothie or shake at home, you can customize it to meet your needs. If you're looking to lose weight, use low-fat or plant-based milk, lower-calorie protein powder and fruits and vegetables. If you're trying to gain weight, use whole milk, higher-calorie protein powder, fruits and vegetables, then add calories with peanut butter, flaxseed, avocado or Greek yogurt.

Choose a complete protein

When selecting a protein powder, choose a complete protein. Animal-based protein powders are complete proteins, but not all plant-based options are. Incomplete proteins, like collagen peptides, don't have all nine essential amino acids. So, they shouldn’t be used as your only protein source. However, collagen powders can be used alongside complete protein sources to provide potential gut, joint, skin, nail and hair health benefits.

Watch for added sugar

Look for protein powders and shakes with very little or no added sugar to avoid sugar spikes or unwanted weight gain. Consider avoiding sugar alcohols, which can cause gastrointestinal distress.

RELATED: Should cancer patients avoid sugar? 5 things to know

How can I add more protein to my diet?

First, focus on eating healthy foods. At meals, this might look like filling two-thirds of your plate with whole grains, vegetables, fruits, beans, nuts and seeds. The remaining one-third can be lean animal protein or plant-based protein.

If you’re able to include protein in your three daily meals and snacks, you're doing great. If you’re struggling to meet your protein needs, try these tips.

Don’t skip meals

If you find yourself skipping a meal like breakfast, try adding a protein shake instead of skipping the meal altogether. That way, you are still getting protein, calories and nutrients.

Stock up on grab-and-go protein sources

Options like hard-boiled eggs, string cheese, jerky sticks and protein bars are protein-packed and packable.

Add protein to your favorite dishes

Here are some ideas to help you incorporate protein into dishes you enjoy.

• Add a protein source to your pasta, salad or stir fry.
• Top your salad with nuts or seeds.
• Add nuts or seeds to cereal or oatmeal.
• Add beans or lentils to soup.
• Add cheese to a sandwich, wrap or burger.
• Make a protein smoothie or shake.

Customize protein sources to your lifestyle

Not all protein options are right for every person, so find what works best for you.

Fibrous options like beans add protein. But if you have a sensitive stomach, they can also leave you feeling gassy or bloated. If that sounds familiar, swap beans for a lower-fiber protein like tofu or tempeh.

Not everyone eats animal products or tolerates dairy. Instead, you can choose plant-based protein sources like whole grains, nuts and seeds.

Denser meats like steak and grilled chicken can be difficult to eat if you don’t have an appetite or have trouble chewing. Instead, lighter, softer options — think chicken or tuna salad, white fish, eggs or tofu — may be easier to eat and digest.

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