What’s your take on protein in our diet? Is more better? Is it the magic bullet to make you leaner and stronger? Should you include a healthy portion at each meal? Do you add protein powder to your smoothies? In order to make healthy food choices, we need to know how much we need and where to get it.
When it was discovered in 1838, protein was named after the Greek word proteios meaning “of prime importance.” Since then it has been hailed as the building blocks of life, and meat and dairy earned the title of “perfect” and “complete” proteins. Along with fat and carbohydrates protein is one of three macronutrients in the human diet. But while protein wins the popularity contest, fat and carbs have been demonized by numerous fad diets. The truth is somewhere in between. We need all three macronutrients in a healthy ratio. Studies show that ideal ratio is found in a diet high in carbs, low in fat, and moderate in protein.
How much do we need?
This is where the perception problem comes in. When college athletes were surveyed on their ideas of protein requirements the majority had no clue. Thirty-three percent indicated a recommended intake of 8.7 grams per kilogram of body weight per day. That’s 11 times the RDI (recommended daily intake)!
For the average person, based on a healthy weight, the National Academy of Sciences, Institute of Medicine recommends eating 0.8 g/kg/day. For a 175-pound man, that translates to 63 grams of protein each day. A 125-pound woman would need about 45 grams.
body weight (in pounds) x 0.36 = recommended protein intake
That’s not what the average American is eating. We typically eat 115-150 grams (15-20% of our diet) each day. We are going a little heavy on the protein. In fact, these figures reflect not what is optimal for the average person, but are equivalent to what the American Dietetic Association recommends for endurance athletes!
Yet even some consider the government’s recommendation (0.8 g/kg/day) too high. The World Health Organization recommends only 5% of daily calories be from protein. Advocates of whole-food plant-based nutrition such as T. Colin Campbell of Cornell University recommend no more than 8-10% of total daily calories be protein. He advocates getting all of your daily protein from plant-based sources.
Campbell and a growing number of others involved in health, nutrition and bio-chemical research see the dangers of consuming excess animal protein. One of the most compelling reasons is IGF-1 (insulin-like growth factor), a hormone found in animal products such as dairy. IGF-1 plays an important role in our growth as children, yet when we are continually exposed to high levels of it throughout our lives, the effects can be harmful. IGF-1 is tied to accelerated aging and has been shown to promote growth in cancer cells. Campbell’s life-long research has shown that consuming levels of animal protein higher than 20% can turn on the growth of cancer cells in laboratory animals, while consuming levels at or less than 5% can actually turn off cancer cell growth.
This makes a lot of sense when we consider milk. Whether from a cow, a goat, or a human, its natural function is to fuel the growth of an infant mammal. Yet we when we continue to consume dairy products beyond infancy, we run the risk of promoting unwanted cell growth in our bodies.
What sources of protein are best?
Most people think that meat, dairy, and eggs are the best sources of protein. It’s a message that’s been reinforced by the American meat and dairy industry for the last century. Many now know that grains such as quinoa, beans and nuts are also protein rich. Yet few realize that vegetables are a valuable source of protein AND a powerhouse of micronutrients.
Compare 100 calories of sirloin steak (1.61 oz) and broccoli (10 oz).
||Broccoli (100 calories)
||Sirloin (100 calories)
See a full nutritional breakdown along with figures for romaine and kale here. Other protein-rich vegetables include spinach, asparagus, carrots, and cauliflower. Protein can also be found in avocado, tomatoes, bananas and many other fruits.
As the chart illustrates, plant-based protein sources provide the energy-giving complex carbohydrates with very little fat and no cholesterol. At the same time fruits and vegetables are the single best source of vitamins, minerals and phytochemicals that protect us from disease.
Of course beans and legumes are versatile, inexpensive and a delicious source of protein. One hundred calories of black beans (less than ½ cup) has about 6 grams of protein and the same amount of fiber. Tofu contains 11 grams of protein per a 100-calorie serving.
In case you’re still not convinced that humans can get adequate protein from plants, consider some of the largest and strongest mammals on the planet – the elephant, giraffe, buffalo, gorilla and the rhinoceros. Herbivores — all of them.
A true protein-deficiency is extremely rare. As long as you are consuming adequate calories (not entirely from junk food or fruit), then you are getting plenty of protein. Don’t spend your money on protein powders and supplements. The best sources are unprocessed, low-fat and come naturally “packaged” with fiber, vitamins, and minerals, such as vegetables, beans, lentils and nuts. Vegans and vegetarians should beware of high-carb and overly processed food choices that are low in nutrition (aka vegan junk food). Concentrate on eating a wide variety of whole foods in your diet, and you will easily consume the optimal amount of protein while protecting yourself from disease.
How Much Protein Do We Really Need?, Jeff Novick, MS, RD
Physicians’ Committee for Responsible Medicine, The Protein Myth: The Building Blocks of Life
Mind Body Green, 10 Vegan Sources of Protein
Dr. McDougall’s Health and Medical Center, George Goff: Triple Bypass Surgery (video)
Reggie Bush Image Courtesy MilkPep/Body by Milk.