Because this specific entry tackles one of the biggest keys to proper nutrition and health it's pretty long, but if you're curious why some diets work for some people and not for others, why Eskimos didn't get heart disease, why you might like the name Pottenger though it sounds funny and such things, you won't be disappointed.
I'd like to start this series of blogs with an installment about metabolism. In my opinion the beginning of understanding nutrition and health is in understanding metabolism. And the beginning of understanding metabolism, well, that's actually in evolution, but for all intents and purposes we can start with Eskimos* about a 1000 years ago.
For the vast majority of human history people couldn't readily buy plane tickets so they stayed relatively isolated from each other in their respective regions of the world in their respective climates, which included some of the most hostile weather conditions. For example, the climate surrounding the North Pole, which is where Eskimos lived and in part still live, is essentially a snow and ice desert that makes Boston winters seem warm by comparison. Beside the cold, another downside of feet of ice covering the earth is that it's pretty hard for plants to grow, so as a consequence a traditional Eskimo diet consisted mostly out of fish, blubber and meat from seals and the occasional whale. In other words, they ate loads of protein and fat, ate nearly nothing but protein and fat to the point where our GPs today would proclaim death sentences on them and bury them in a mountain of cholesterol reducing drug prescriptions. But the fascinating thing is that Eskimos on a traditional Eskimo diet were free of degenerative diseases like diabetes or heart disease. How come? The answer is simply that they were adapted to their environment in every way including their biochemistry, that is, their metabolism. Just like every single population on this planet was adapted to their environment and the foods present in their environment.
So what does this have to do with your metabolism? Well, let's think, still 1000 years ago, of tribes near the equator where the climate allows plantlife to flourish all year round. Their diet consisted mostly out of fruits and vegetables and only of a little bit of fat and meat that they would catch on occasion. Yet, they too didn't have any degenerative heart diseases and flourished in their environment. But if you started feeding them nothing but fat and protein, they would have gotten sick. Just like an Eskimo would have gotten sick on a diet that predominantly consisted out of fruits and veggies. Their biochemistry was unsuited for efficiently converting such food into fuel.
Today, especially here in America, we may no longer be physiologically adapted to our environment, but we still carry the genes that made our ancestors flourish on one type of food and perish on another. So in that regard, we all have unique biochemistry, and roughly in the last 100 years, the term metabolic type was developed to refer to that biochemical uniqueness. Basically, just like none of us are identical on the outside (save maybe for identical twins), none of us are identical on the inside. It's one of the most common sense things, but for some reason current marketing trends are still selling a universally applicable diet—something that simply doesn't exist.
What is a metabolic type? Just like every other human characteristic, metabolism is on a continuum, but that continuum can be divided into 3 major categories—a protein type (like Eskimos), a carbohydrate type (like the populations near the equator) and a mixed type (likely descendants from regions where people had to rely on plants and meat approximately equally).
How do the different metabolic types work? This is a simplification, but essentially your metabolism is your personal fuel furnace** that keeps your body in balance. You have people who are fast oxidizers, meaning their biochemistry processes food quickly, and slow oxidizers whose biochemistry breaks food down more slowly.
If you're a fast oxidizer and you eat, let's say an apple (lots of carbohydrates that are broken down easier than fat or protein) your body will process it very quickly, you'll have a sugar high and a crash and you'll feel tired and hungry again very soon afterward because that particular food puts that particular body out of balance. However, if you're that same fast oxidizer and you eat a chicken breast (lots of protein and some fat both of which take a longer time to be broken down), your body will break it down at a balanced rate that will keep you energized and satiated for longer. On the other hand, if you're a slow oxidizer and you eat a chicken breast or a steak, your body will take so long to process it that you will feel heavy and lethargic. So the key to converting food into fuel efficiently is to give your body the foods that will keep it balanced so that you can sustain a stable level of energy and clarity.
As you might have already guessed, fast oxidizers tend to have protein metabolic types, slow oxidizers tend to have carbohydrate metabolic types, while people who are energized by both nutrient groups are the mixed metabolic types (like myself).
How do you find out what metabolic type you are? There are several routes to finding this out and most of them lead to you putting your money into someone else's pocket. I really am not a big fan of buying concepts, especially diet concepts so I honestly don't recommend spending money on getting a metabolic type test. However everything I read about people who have struggled with weight and then finally gotten their metabolic type assessed, have lost weight and changed their life for the better has been highly encouraging. So whatever you choose is really up to you, just keep in mind I'm not promoting any of these products, ... I'm more saying these methods exist.
- One method is a book. It's called the Metabolic Typing Diet by Wolcott and Fahey and why it's called a “diet” I don't know. The book explains the research and science behind metabolic typing. It also has a questionnaire you can follow that will help you determine your metabolic type. I got this book as a gift which means I have it, which also means (at least for my Boston friends) that if you'd like to borrow it, feel free to ask. And that reminds me, check your local library. Maybe they have it, too.
- Another method would be to go to a specialist certified in metabolic typing and get tested with a more sophisticated questionnaire. If you're keen on this, check out Sean Croxton. He is a very down to earth personal trainer with a wealth of information. I started most of my research with his YouTube posts and his website. Even if you don't want your metabolic type assessed, he's a great source, and here is one of his short videos if you'd like more information about metabolic typing.
- The simplest method of figuring out your metabolic type would be just to pay attention to what your body is telling you. Do you feel tired after you eat a particular food? Do you feel energized? full? Or does it make you hyper and then you crash? Just be aware that while some foods are bad for everyone (i.e. highly processed, sugar-loaded, empty calorie stuff) some good foods are good for some while not that great for others. We all have unique internal chemistry.
Does eating according to my metabolic type make me lose weight? The simple answer is yes. To explain this without exceeding the scope of this blog, you will have noticed that I referred much to macronutrients (proteins, fats, carbohydrates) but not to calories. Calories are merely units of energy (namely one calorie being the amount of energy needed to raise one gram of water to one degree Celsius) and they measure the energy that our bodies need to perform metabolic functions. However where you get your calories matters too. In order to be healthy you need a balance of nutrients, you need carbs, protein and yes, fat. If you're a carbohydrate metabolic type you need half or more than half*** of all your calories to come from carbohydrates in order to maintain optimum energy and health. If you have too little or too much of the wrong nutrient, you get sick, namely you get malnutrition. And the most prevalent type of malnutrition in America is obesity. Go figure. The phrase “junk food” is applicable to junk food because the food is poor in its nutritional value and has loads of empty calories. If you give your body the right nutrition it will keep you healthier and leaner.
But speaking of leaner, here is one last thing about metabolism being a furnace. Your metabolism helps you burn calories, so if you're interested in losing weight it's in your best interest to keep your metabolism going at full blast, and here are a few tips as to how to do that:
- Eat breakfast. Your body is starved after 8 (did I say eight, ha! after the few) hours of sleep you manage to get at night and to give it energy to get it going, you should eat breakfast.
- Eat small meals every 3-4 hours. Whenever you put anything into your body, your metabolism kicks in and starts breaking it down. Furthermore, eating small meals throughout the day keeps you from getting famished and starving and thus keeps you from overeating later on.
- Eat your biggest meals earlier in the day and have a smaller dinner so that you have energy for the most strenuous parts of your day.
- Some research shows, and I didn't really look too deeply into this, but it makes chemical sense, that eating lean protein together with complex carbohydrates gives your metabolism the greatest boost in terms of the amount of work it has to do. (If you want to double-check this info, it's sometimes referred to as the thermal value of food and I read it in Tosca Reno's book. You can google her.)
- If you stop eating or drastically cut your calories, your metabolism slows and you are more likely to gain weight that way because you've got nothing burning your calories. So for your own sake, don't cut calories like crazy.
That's all folks. Thanks for sticking through the long blog. Consider it a big breakfast and now that we're on the way, we can make the portion sizes smaller. Next week, I'll be writing about milk and soy and the mountain of misconceptions surrounding this topic.
Till then ...
“It is not what disease the patient has, but which patient has the disease.”--attributed to William Osler
*I am aware that some Eskimos prefer to be called Inuits, but for the sake of simplicity I chose to use the word Eskimo as the umbrella term encompassing a few different native populations in the circumpolar region.
**I'd like to thank Lindsey H. (D.O. in the making) for answering several of my metabolism questions and giving me the furnace analogy. Good luck in med school. =)
***for more information on the foods pertinent to the metabolic types check out the Price-Pottenger Nutrition Foundation