“Animal protein is the best protein you can get.”
“People need at least 1 gram of protein per pound of body weight.”
“Don’t eat too much protein, the excess turns into fat.”
If you have heard statements on proteins similar to the ones above, you are probably aware that in addition to the complexity of protein’s role in the human body, there are many stubborn views on protein and its consumption.
Let’s answer three questions about protein that are not as clear as health gurus or nutritionists would like them to be (because where’s the fun in that?).
It is important to know what proteins are. Proteins are long, complex strings (or combinations of strings) composed of amino acid building blocks. (1) Think of a protein as a beaded necklace, where the properties of each bead determine the overall aesthetic of the protein. (Almost like a necklace your little sister makes for you, except your sister is Mother Nature).
Proteins fight foreign particles as antibodies, complete thousands of chemical reactions as enzymes, transmit critical biological signals as messengers, provide essential structural support to cells as building components, and move other key molecules as tiny vehicles of transportation. (1)
Now that we have covered the basic principles, let’s answer more difficult questions regarding consumption of foods with protein.
1.) Animal protein is better than plant protein, right?
All protein-filled foods are not created equally. This does not mean that certain foods with protein are better than others. For example, Vernon R. Young and Peter L. Pellett (with University of Cambridge, London University, and shared MIT affiliations) published a respected study in the American Society for Clinical Nutrition in 1994. In it, they elucidate common misconceptions about plant versus animal protein: the largest misunderstanding being that plant protein is “incomplete.” (2)
Plant nutrients eaten in combination are just as “good” as animal protein. For example, leafy greens, lentils, seeds, and grains provide a complete amino acid profile. Plant nutrients also contain all amino acids, but some are present in smaller quantities compared to animal protein. Mixing a variety plant protein sources is important to create a complete amino acid profile. The most important takeaway is to balance your nutrient intake; plant-based foods are packed with essential vitamins and minerals some animal foods cannot provide, and vice versa. Picking the right mixture of foods to eat is key.
2.) How much protein should I really eat in one day?
In general, athletic people need more protein and sedentary people need arguably less. During exercise, “more amino acids and proteins are used by the body." (3) If an individual expends an excess of amino acids and proteins, he or she will need to replace them for a healthy body. So, how many grams of protein do you need to eat in a day?
Popular advertisements would have you believe the more protein in your diet the better, but you are wiser than that. The Food and Nutrition Board of the Institute of Medicine recommends about 0.4 grams of protein per pound of body weight. (4) For a 160 pound man, that is around 60 grams of protein; for a 120 pound woman, that is around 40. Obviously, people are a range of different heights and weights, so protein requirements differ. Interestingly, this recommendation is very modest, and most people eat more grams of protein than the guideline suggests. Studious talked with Dr. Christopher Gardner, Professor of Medicine with the Stanford Prevention Research Center whose work focuses on special diets in health and nutrition. He notes that “Americans get ~16% of their calories from protein.” (5) Based on an average 2,000 calorie diet, this turns out to be 80 grams of protein.
Unfortunately, there are no absolute numbers to follow. Protein research is evolving and the jury is still out. However, do not be afraid to consume extra protein in your diet. More importantly, take heed of your protein sources, covered in the next question.
3.) If I eat too much protein, does it turn into fat?
Technically, yes; protein (and carbohydrates) can be converted to fat for energy storage. You must eat extra food beyond your normal requirements to acquire excess protein, which inevitably leads to an increased caloric intake. Any calories (energy units) your body does not use are thus not expended. Calories that are not used are stored in the body, and any stored calories could eventually turn into fat. Eating an excess of any macronutrient can lead to fat storage.
Dr. Gardner also says, “the issue [of protein consumption] becomes extremely complicated when you start trying to disentangle the amount of protein from the sources of that protein.” (5) Studies on high-protein diets are ongoing, but a key complication is where a diet’s source of proteins originate. In question one, we established that all foods with protein are not created equally. Eating portions of steak, beans, or fish with equivalent protein levels will have different macro-nutrient profiles; each serving will also have varying calorie counts. Being mindful of where your protein is coming from is more beneficial than limiting your overall protein intake.
Hopefully these 3 misconceptions on protein have been elucidated, and you now understand the nuances of this nutritional staple.
Thank you to Dr. Gardner for his Studious contributions this week!
1. ‘What Are Proteins and What Do They Do?’ Genetics Home Reference. US National Library of Medicine, National Institutes of Health, Department of Health & Human Services, 18 Aug. 2015. Web. 25 Aug. 2015.
2. Young, Vernon, and Peter Pellett. ‘Plant Proteins in Relation to Human Protein and Amino Acid Nutrition.’ American Journal of Clinical Nutrition 59.5 (1994): 1203S–1212S. Print.
3. Knight Caffery, Lee. ‘How Much Protein Do Athletes Need?’ Vanderbilt Health Psychology. N.p., n.d. Web. 26 Aug. 2015.
4. A Report of the Panel on Macronutrients. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) (Dietary Reference Intakes). Washington, D.C: National Academies Press, 2005. Print.
5. Gardner, Cristopher. Studious E-Mail interview. 24 August 2015.