Part 2: Keep Your Metabolism Going
For many years, I subscribed to the notion that constantly eating throughout the day was great because it "kept my metabolism going." When I woke in the morning, whether I was hungry or not, I'd suck back three eggs and toast to "kickstart my metabolism." Then, I'd eat something every 2.5 to 3 hours without fail. I was a machine. I was certain that it was the right thing to do, as I'd read so many articles and heard so many health experts preach the benefits of doing so... but was it really helping me stay lean? And more importantly, was it healthy?
"Metabolism" is one of those buzz terms we hear all the time, but I never really understood exactly what it meant until fairly recently. So, to define some terms here, when I use the term "metabolism" throughout this post, I'm referring to what's called the "Resting Metabolic Rate" or RMR. I'm focusing on RMR, because that is what we spend the most time in. Unless you're an athlete who's training all day long, we spend most of our day at rest. Therefore, our Resting Metabolic Rate uses the majority of the body's daily energy budget. In other words, we burn more calories each day while at rest than during our hour-long workout. So, in order to control your weight, it's your RMR that has the greatest impact.
Now, when it comes to weight management, if you take two people who each consume 2400 calories of the exact same foods and exercise the same amount each day, the person with the faster metabolism will indeed have an easier time losing or maintaining their weight. Think of your metabolism like a machine, and when you eat the machine speeds up in order to process the incoming food. The more you eat, the faster the machine goes. This is the reason everyone thinks a fast metabolism is the holy grail.
But, weight management aside, does a faster metabolism help you live longer? Does it increase your longevity? Many studies over the past century indicate, it does not. In fact, those with a slow metabolism consistently live longer... up to 30% longer (Source 1)!
Let's go back to the machine analogy. With a fast metabolism, and doing things to increase metabolism (like eating every 2.5 to 3 hours), your body is constantly running at high speeds. Like any machine, the faster and more often it's running, the quicker it will wear out. Thus, contrary to popular belief, to live longer our goal should be to slow down our metabolism, not speed it up.
So, what can we do to slow down our metabolism? The two best ways to slow down our metabolism is to eat less and to eat plant-based foods that are high in nitrates (dark leafy greens, etc.) (Source 2). Might this be why restricting the amount of calories through fasting or simply eating less on a daily basis leads to a longer life? In rats and other animals, when you restrict caloric intake it can lead to up to a 50% longer lifespan (Source 3)! Perhaps this is also why all five of the Blue Zones (the areas of the world where people live the longest) consume far less calories daily than the average westerner? Furthermore, is this why all five of the Blue Zone populations eat plant-based diets loaded with nitrates?
When we eat less throughout the day or practice intermittent fasting (better defined as "not stuffing our faces all day") our bodies spend less energy on metabolizing and digesting food and have more energy for everything else (like fighting disease). Our bodies are incredible healing machines, but most of us are constantly throwing crap into the machine and are bodies are forced to deal with it. The more we can get out of our body's way and let it heal itself, the better off we may be. For more on this, see my previous post The Greatest Health Tool You're Not Using.
In conclusion, if you're eating more and more often in an attempt to "keep your metabolism going" for purported health benefits, you have been mislead, just as I had. Might eating more frequently speed up your metabolism and help burn more calories, yes. But, why not just consume less overall calories (ideally from high nitrate plants)? Then your body (the machine) will work less and you'll achieve both your desired weight and increase longevity at the same time.
Just as I never questioned consuming certain foods (animal products, in particular) for the first 25 years of my life, I also never questioned eating "breakfast," "lunch," and "dinner." Both of those things were so normal to me... but the more I dive into the actual science, I have found that "normal" rarely equals healthy.