The Big Three

How Macronutrients Fuel Your Body

What is protein?

Protein helps build and repair your body—like muscles, skin, and organs. Protein is made of smaller parts called amino acids. [15]

Animal vs plant protein

Animal proteins come from foods like meat, fish, eggs, milk, yogurt, and cheese. Plant proteins come from foods like beans, lentils, soy foods (tofu/tempeh), nuts, seeds, and whole grains. [16,15]

Two platters labeled 'Animal Protein' and 'Plant Protein' with respective food items.
Hand applying a bandage to another hand on a beige background
Man stretching in a gym setting

What can be bad about not getting enough protein?

Not enough protein can lead to:

  • Muscle loss or weakness.
  • Slower healing after cuts or illness.
  • In kids, slower growth.

[15]

What can be bad about getting too much protein?

For most healthy people, higher protein can be fine, but very high protein can be a problem if it:

  • Crowds out other foods you need (like fruits, vegetables, and whole grains).
  • Comes mostly from processed meats (like bacon, hot dogs, and deli meats).

Processed meats are linked with higher colorectal cancer risk, so health groups often suggest limiting them. [18]

People with chronic kidney disease may need a lower‑protein plan unless they are on dialysis. Always follow your clinician’s guidance. [19]

Graph with a red upward arrow and 'Cancer Risk' text on a white background
Transparent human body with highlighted heart, DNA strands, and molecular structures on a white background

Food examples (protein)

Protein amounts below are typical estimates. Values are based on USDA FoodData Central. [20]

Food

Typical serving size

Protein (g)

Chicken breast (cooked/roasted)

3 oz (85 g)

26.4 g

Turkey breast (cooked/roasted)

3 oz (85 g)

25.6 g

Lean ground beef (90–94% lean, cooked)

3 oz (85 g)

21.3 g

Salmon (Atlantic, cooked)

3 oz (85 g)

18.8 g

Tuna (canned in water, drained)

3 oz (85 g)

20.1 g

Shrimp (cooked)

3 oz (85 g)

20.4 g

Hard-boiled egg

1 large (50 g)

6.3 g

Whole milk (3.25%)

1 cup (244 g)

7.7 g

Plain nonfat Greek yogurt

1 container (170 g)

17.3 g

Cheddar cheese

1 oz (28 g)

6.5 g

Food

Typical serving size

Protein (g)

Cooked lentils

1 cup

17.9 g

Cooked black beans

1 cup

15.2 g

Cooked chickpeas

1 cup

14.5 g

Firm tofu

1/2 cup

21.8 g

Tempeh

~3 oz (about 85 g)

~17 g*

Seitan

2 slices

24 g

Cooked quinoa

1 cup

8.1 g

Dry oats

1/2 cup (dry)

6 g

Peanut butter (smooth)

2 tbsp

7 g

Almonds

1 oz

6 g

Pumpkin seed kernels (dried)

1 oz

8.6 g

Chia seeds

1 oz

4.7 g

Unsweetened soy milk

1 cup

7 g

Extra note: Vitamin B12

Vitamin B12 is found naturally in animal foods. If someone eats no animal foods, they often need B12‑fortified foods or a supplement to avoid deficiency. [17]

References

References

Numbers in the text match this list. Accessed February 9, 2026.

  1. MedlinePlus (NIH). Nutrition. https://medlineplus.gov/nutrition.html

  2. CDC (NCHS). Nutrition (Health, United States): macronutrients and chronic disease risk. https://www.cdc.gov/nchs/hus/topics/nutrition.htm

  3. MedlinePlus (NIH). Carbohydrates. https://medlineplus.gov/ency/article/002469.htm

  4. MedlinePlus (NIH). Dietary Fiber. https://medlineplus.gov/dietaryfiber.html

  5. World Health Organization (WHO). Guideline: Sugars intake for adults and children (2015). https://www.who.int/publications/i/item/9789241549028

  6. USDA Nutrition Evidence Systematic Review (NESR). Sugar-sweetened beverages and risk of type 2 diabetes: systematic review (Nov 2024). https://nesr.usda.gov/sites/default/files/2024-11/Sugar-sweetened-beverages_type-2-diabetes-2025DGACSystematicReview.pdf

  7. CDC. About Cavities (Tooth Decay). https://www.cdc.gov/oral-health/about/cavities-tooth-decay.html

  8. American Heart Association (AHA). Whole grains, refined grains, and dietary fiber. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/whole-grains-refined-grains-and-dietary-fiber

  9. BMJ. Whole grain foods and risk of type 2 diabetes: meta-analysis summary. https://www.bmj.com/content/370/bmj.m2206

  10. MedlinePlus (NIH). Dietary fats explained. https://medlineplus.gov/ency/patientinstructions/000104.htm

  11. American Heart Association (AHA). Fats in Foods. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fats-in-foods

  12. USDA Food and Nutrition Service (FNS). Dietary Guidelines for Americans (current edition). https://www.fns.usda.gov/cnpp/dietary-guidelines-americans

  13. MyPlate (USDA). More Key Topics: Oils, Added Sugars, Saturated Fats. https://www.myplate.gov/eat-healthy/more-key-topics

  14. NCCIH (NIH). Omega-3 supplements: what you need to know. https://www.nccih.nih.gov/health/omega3-supplements-what-you-need-to-know

  15. MedlinePlus (NIH). Protein in diet. https://medlineplus.gov/ency/article/002467.htm

  16. MyPlate (USDA). Protein Foods Group. https://www.myplate.gov/eat-healthy/protein-foods

  17. NIH Office of Dietary Supplements (ODS). Vitamin B12 fact sheet for consumers (PDF). https://ods.od.nih.gov/pdf/factsheets/VitaminB12-Consumer.pdf

  18. IARC (WHO). IARC Monographs evaluate consumption of red meat and processed meat (Press Release No. 240, 2015) (PDF). https://www.iarc.who.int/wp-content/uploads/2018/07/pr240_E.pdf

  19. National Kidney Foundation. CKD Diet: How much protein is the right amount?. https://www.kidney.org/kidney-topics/ckd-diet-how-much-protein-right-amount

USDA. FoodData Central (nutrition database). https://fdc.nal.usda.gov/