One common criticism of a plant-based or vegan diet is that you can’t get enough protein. I would like to dispel this myth by showing the importance of choosing the right basis of measuring nutrition content and discuss the implications this has on nutrition as a whole.
The Wrong Measurement
If I had a teaspoon of melted butter, which gets 100 percent of its calories from fat, and I pour it into a glass of water, I can now say to you that it is nearly 100 percent fat-free. You would likely insist to tell me that I’m wrong, but may struggle to explain why.
What I’ve done is measure the fat content of the melted butter and water mixture as a percentage of weight, distorting the fact that 100 percent of its calories still come from fat.
This is how nutrition content is commonly measured through — on the basis of weight. We compare the nutrition content of different foods by comparing equal weights of the foods. Does this really make sense?
Our brains do not measure food by weight. We do not feel satiated by consuming x grams of the food. If this were the case, we could just drink more water to feel satiated. Rather, our appetite is controlled by nutrient fulfillment and calories. When we get enough nutrients and calories, our brains indicate to us that we are no longer hungry¹.
So, a better measurement of nutrition would be on a caloric basis. When eating different foods, we tend to eat similar amounts of calories. Calories come from the macronutrients protein, fat, and carbohydrates. Therefore, if I wanted to see how protein-dense a given food is, I should calculate the percentage of calories that come from protein, not the percentage of grams that come from protein. This is the appropriate way to compare and contrast the nutrition content of different foods.
Animal Protein vs. Plant Protein
Now that we have an accurate measurement of nutrition, we can compare the protein content from some common animal and plant sources. The data I used for the visualizations is from the U.S. Department of Agriculture (USDA).
First, let’s take a look at the data using the wrong measurement, as is commonly done:
Clearly, this is where the criticism of the vegan diet comes from. Taking a look at this chart makes it seem like it would be impossible to get enough protein from plant sources alone.
However, if we take a look at how they should be compared — on a caloric basis — it tells a very different story:
I’ll admit, when I first saw this I was shocked! Spinach is more protein-dense than steak! Kale and broccoli aren’t too far behind either. What a change in perspective.
Overall, it is clear that animal sources are still high in protein, but using the appropriate measurement for nutrition levels the playing field. It shows that it is in fact possible to get enough protein on a plant-based or vegan diet.
Why Are We Being Misled?
A natural question is, “why is nutrition calculated in this way if it is wrong?” Truly, I do not know for sure, but I have some suspicions.
In 1991, McDonald’s hopped on the low-fat bandwagon and advertised their McLean Deluxe burger as being 91% fat-free. How was this possible? By calculating fat as a percentage of weight (including the bun and the condiments) rather than as a percentage of calories. In reality, the McLean Deluxe got 49 percent of its calories from fat¹.
Using the data from the USDA, I performed this same numbers trick and graphed the two ways of measuring fat content side-by-side. This demonstrates that by using a nutrient-weight ratio, it is easy to advertise fatty animal products as being low-fat.
This gets at what I believe to be the answer to our question. Nutrition expert and author Joel Fuhrman, M.D. states concisely,
“nutrient-weight ratios hide how nutrient-deficient processed food is and make animal-source food not look so fatty¹.”
There is a great deal of politics and money involved in what nutrition guidelines say, and the meat industry is a major player. Dr. Frank Hu, a professor of nutrition and epidemiology at Harvard and one of the experts who served on the 2015 Dietary Guidelines Advisory Committee, USDA/HHS, says
“the meat industry has historically had “huge influence” on USDA. . .².”
I think it’s fair to say that something is going on behind the scenes. Nutrient-weight ratios hide the fact that animal products are high in fat, which makes them more marketable since fat has historically had a bad reputation.
It also makes processed foods more marketable because they may have more nutrients per gram than per calorie. In reality, though, they are just hiding the fact that these foods are nutrient deficient and contain mostly empty calories.
Now that we know that nutrition should be measured on the basis of calories, we can first rest assured that we will get plenty of protein even if we eat a plant-based or vegan diet.
More importantly, though, we can apply this to good nutrition as a whole. Dr. Fuhrman, in his book, “Eat To Live,” postulates a formula for health:
This formula represents the nutrient-density of your diet. Food gives us not only calories but also nutrients, which are extremely important to our health. Nutrients include vitamins, minerals, fibers, and phytochemicals. The more nutrient-dense foods we eat, the healthier we will be, according to Dr. Fuhrman.
“Eating large quantities of high-nutrient foods is the secret to optimal health and permanent weight control¹.”
- Dr. Fuhrman
When we shift from nutrient-weight ratios to nutrient-calorie ratios, we are equipped to make better food choices and eat healthier!
To illustrate which foods are the most nutrient-dense, Dr. Fuhrman created the aggregate nutrient density index (ANDI). Foods are ranked on a scale of 1–1000, with the higher scoring foods delivering more nutrients per calorie³. This system has been adopted by Whole Foods for certain items.
If you would like to learn more about Dr. Fuhrman’s formula for health and his “Eat to Live Diet”, you can read all about it in one of my favorite books on nutrition, Eat to Live!
: Fuhrman, Joel. Eat To Live. Little, Brown, and Co., 2012.
: Heid, M. (2016, January 08). Food Industry Lobbying and U.S. 2015 Dietary Guidelines. Retrieved June 12, 2020, from https://time.com/4130043/lobbying-politics-dietary-guidelines/
: ANDI Food Scores: Rating the Nutrient Density of Foods. (n.d.). Retrieved June 12, 2020, from https://www.drfuhrman.com/elearning/eat-to-live-blog/128/andi-food-scores-rating-the-nutrient-density-of-foods