I’m constantly asked whether a plant- (vegetables, grains, legumes, fruit) or animal- (meat, poultry, fish and dairy) based diet is healthier. This is the most controversial diet topic out there. In fact, even leading nutrition scientists are at odds over which diet is the best for us. And there doesn’t seem to be an easy winner emerging any time soon.
I’m sure it leaves you scratching your head thinking ‘how can there be so much contradictory information regarding diet and health’? I do at times!
Well, there’s no simple answer because it depends on so many factors including medical conditions; ethical/moral beliefs; religious practices; and cultural/ethnic traditions. For example, a diabetic is healthiest when they follow a carb-poor diet whereas someone with kidney disease is better off limiting protein intake. Then, there are populations that follow certain religious and cultural traditions and thrive on vastly different diets ranging from nearly all animal protein and fat to nothing but nuts and berries, each of which promotes excellent health.
Yet, one reason that provides the best clue as to why people respond so differently to a particular type of diet is ‘nutrigenomics’, defined as the way in which foods we eat affect our genes. What research is finding is that certain foods cause some peoples genes to enhance health whereas others derive no benefit or may even promote disease. What this tells me is there is no ‘one size fits all’ when it comes to a health-promoting diet. But, there are certain foods that seem to turn on genes that promote good health regardless of your genetic makeup and those are the ones we all need to have on our daily menu. Things like fresh, leafy green and colorful vegetables (think spinach, kale, peppers, squash, carrots, sweet potatoes, beets, etc.) and seasonal fruits (mostly berries, cherries, pomegranates, melons, bananas, citrus, etc.), beans and nuts.
In 1986 I began grad school as a nutrition and exercise scientist at Purdue University and the timing was perfect because we were in the middle of the ‘80’s fitness craze. Remember the Jane Fonda “aerobic” workout videos? Many of us had a copy by our TV and I’m not sure I should admit this, but when I visited my parents at holidays and during the summer, I would occasionally go to an “aerobics” class with my Mom. I actually found it helped my flexibility and core strength but it also apparently caught the attention of the instructor and she invited me to join her for filming a few classes for a local TV station. I reluctantly agreed and soon appeared on TV every Sunday and Wednesday teaching “aerobics”. What was I thinking?
Another benefit of being in grad school during this time was the abundance of late-breaking research and information on all things related to health. I had just completed my undergraduate degree and a successful career as an NCAA scholarship-athlete so I was determined to remain fit and healthy because I wholeheartedly believed, still do, that if you’re going to talk the talk you better be able to walk the walk. So it goes without saying I became a massive sponge for all things nutrition. One diet approach that kept surfacing in my journal readings, due to its reported health benefits, was vegetarianism… I loved all things plant-based so I gave it a try. It also made a lot of sense because rice and beans were cheap and they fit my grad school budget! Vegetarianism also intrigued me because it was a relatively new way of eating with little, if any, scientific data regarding its effect on metabolism and body weight. Within weeks, with the help of my advisors, I had designed my first research study, to test the effects of a vegetarian diet on resting metabolism, which included both the calories burned at rest and those burned after eating a meal (called thermic effect of a meal, TEM).
Our focus on metabolism was prompted by the observation that vegetarians may weigh less than non-vegetarians and we wanted to know whether a higher metabolism played a role. So, I recruited an equal bunch of my plant- and animal-eating friends and measured how many calories they burned in a resting state as well as following a meal. I did have to dip into the local Seventh Day Adventist community to pick up a few extra ‘veggies’. Surprisingly, we found that a vegetarian diet burns 25% less calories following a meal (TEM), compared to a non-vegetarian diet. This was the opposite of what we expected because weight loss is usually associated with burning more calories, not less. But, the thing that really hit home for me was that if I kept eating a typical vegetarian diet with the majority of calories from carbs (>60%) I would burn fewer calories and over time this may lead to weight gain, not weight loss! This was my epiphany that set me on a path of discovery that would challenge traditional dogma to this day. Don’t get me wrong, I continue to eat tons of plants, mostly from green leafy and colorful veggies, with a balance of whole grains and fruits. But, I always eat my veggies with the proper amount of healthy lean proteins from both animal (wild fish, grass-fed beef, and free-range poultry) and plants (legumes, nuts, and seeds).
Remember, I conducted this study in the mid ‘80’s during the low-fat, high-carb craze that is now known for initiating the current obesity epidemic. And here I was challenging the high-carb dogma that was the basis of the food guide pyramid at the time. Even so, we published the paper in the world’s leading nutrition journal (American Journal of Clinical Nutrition). Finally, I find it interesting that it took so long for others to realize the health benefits of a diet containing increased protein (>20%) and moderate carbohydrate (<50%). This ground-breaking early research study has been the basis of my Protein Pacing diet ever since. I invite you to join me at the Protein Pacing table of optimal health and nourishment!