The classic cartoon hero Popeye was an early champion of plant-based protein demonstrated in his theme song, “I’m strong to the finish ‘cause I eats me spinach….” For years mothers, including my mother, used Popeye as an example to encourage their children to eat spinach because it would make them healthy and strong. Nutritional science has proven once again that Mom was right — approximately 51% of the calories from spinach are protein!

Today, protein is synonymous with animal products and the majority of meals are built around a meat centerpiece. Vegetables have been relegated to a garnish or small side dish that is all too often oiled and overcooked. Where did this dietary concept originate? The word “protein” is derived from the Greek word proteios, meaning “ of prime importance,” perhaps explaining its preeminent position in dietary discussions today. Also, throughout history meat-based meals were a symbol of an affluent lifestyle while those of the lower classes consumed a “substandard” plant-based diet. The unspoken cultural assumption that persists today is that a plant-based diet is inferior and deficient in protein and contributes to a weakened body.

The good news is that the growing body of nutritional research is illuminating the fallacy of this cultural myth. Research has shown that all plants contain protein and at least 14% of the total calories of every plant are protein. Broccoli contains more protein per calorie than steak and, per calorie, spinach is about equal to chicken and fish. Of course, you’ll need to eat a lot more broccoli and spinach to get the same amount of calories that you do from the meat.

Multiple studies have shown that if you are meeting your caloric needs through plant-based nutrition, you will satisfy your body’s protein requirements. Some simple math proves the point. If you consume 2000 calories per day from plant sources containing 14% protein, the total number of calories from protein equals 280. Divide 280 calories by 4 ( there are 4 calories per gram of protein) to find that this diet would supply 70 grams of protein — more than enough for the average man or woman. Classic studies of protein nitrogen balance have shown that women require, on average, 30-50 grams of protein per day and men require 50-70 grams per day based on weight.

Nutritional research has also discovered that plant-based protein from a wide variety of sources adequately supplies all the essential amino acids required for a healthy body. It is not necessary to consume a “complete” protein at every meal. The body’s innate intelligence utilizes the protein from multiple meals to provide the necessary building blocks. In addition, every bite of plant-based protein offers the extra health benefits of fiber, antioxidants, phytochemicals, vitamins and minerals.

How can you add more plant-based protein to your diet? By simply eating more plants. Beans (27% protein) lentils (36%), chickpeas (33%), peas (30%), and kale (22%) provide the greatest opportunity to acquire micronutrients packaged with protein. Practical solutions to add more of these include adding beans/legumes to salads, stews and soups. Use higher protein vegetables like spinach, kale, lentils, broccoli, beans and peas in each meal or recipe. And for a nutrient-rich breakfast, consider starting your day with a smoothie made with bananas, blueberries, kale, spinach, strawberries and fresh almond milk.

So, now you too can claim, “…I’m strong to the finish, ‘cause I eats me spinach” …and kale…and lentils…and chickpeas…and beans!

Dr. Scott Stoll is a board certified specialist in Physical Medicine and Rehabilitation and currently serves as the medical director for the Center for Advanced Spinal Solutions at Coordinated Health, chairman of the department of Physical Medicine and Rehabilitation and team physician for Lehigh University and the United States Bobsled Team. He currently serves on the Scientific Medical Advisory Board for Whole Foods Market and serves as Chairman of the Nutritional Board of Advisors for Eat Right America.