Carbs are probably the most confusing and debated of the macronutrients. Some say good carbs, some say low carbs, some say high carbs, some say no carbs! Is everyone right? Is no one right? Let’s look at what carbs are and what they do, and then we’ll figure out what we should be eating.
What Are Carbs?
Carbohydrates are sugars. Any food that breaks down into molecules of sugar is a carb. There are two kinds of carbs: simple and complex. Simple carbs are made up of one or two sugar molecules stuck together. Simple carbs are any type of sugar or processed/refined carbs like flour. Complex carbs are made up of three or more sugar molecules. You find these in your veggies and fruits. Not too complicated. The important difference is what happens when these sugars are eaten.
Because simple carbs are already in such a basic form, it takes very little work for your body to break them down and absorb them. This means that the time from the food going into your mouth to the sugar hitting your bloodstream is relatively short. I should clarify: It isn’t just that the sugar is hitting your bloodstream quickly, but that ALL of the sugar is hitting your bloodstream ALL AT ONCE. Here’s what happens. Let’s imagine you get to work at 9 a.m. and indulge in a delectable doughnut. Now a series of events takes place. First, as the morsel digests and gets absorbed, your blood sugar levels spike. That’s when you get a “sugar high.” It is 9:30, and you are feeling great! That sugar high triggers a big release of the hormone insulin. Insulin controls blood sugar levels by telling your cells to take in and store the excess sugar in your blood. So your cells all start snagging the sugar like a giant game of Hungry Hungry Hippos, and they store it, either as glycogen (we’ll get to that) or as fat. Because your brain runs almost exclusively on sugar from your blood, it is feeling a bit neglected at this point. It is now 10:20. You know, right about when you start dozing at your desk. Thanks, doughnut. It was a great ride.
Complex carbs are more . . . well, complex. It takes longer for these to get broken down and absorbed in your body. Because the breakdown is slower, so is the increase in blood sugar. Instead of a huge spike all at once, you get a more gradual and steady increase over a longer period of time. A milder increase in blood sugar means a milder release of insulin, which means no sudden crash (your brain and boss thank you) and no deposits to the ole love handles.
Why Eat Carbs?
While carbs aren’t technically necessary for life (like protein and fat are), they do serve some good purposes in your body. Glucose (sugar) is your brain’s prefered source of energy— hence the sugar high. Your liver stores glucose so that it can be released into the bloodstream when blood sugar is low. That is where your brain gets it from. Glucose is also stored and used by muscle cells for energy. However, unlike in the liver, once glucose is stored in a muscle cell, it can be used only by the muscle cell.
I want to share a little more about the storage of carbs in the body so you have a better understanding of what’s going on and can make informed choices. First off, carbs get stored as glycogen, which is just a chain of glucose molecules all stuck together. As mentioned before, this gets stored only in the liver or muscle cells (unless you have glycation happening, which probably means you are an out-of-control diabetic). Your body can store about 500 grams of glycogen at a time. For reference, this is enough to fuel your body for about 90 minutes of low-intensity exercise (distance running) or about 20 minutes of high-intensity exercise (CrossFit). Beyond those domains, you need to either replenish your glycogen or start burning something else (like fat).
High Carb or Low Carb?
The reason I bring up all this storage stuff is to address the concept of “carb loading,” which is when you eat large amounts of carbs leading up to an athletic event to try to ensure full stores. This is a common practice in endurance sports and, in my experience, is fully subscribed to in many other sports. How many of you had a high school or college coach tell you to eat a big pasta meal the night before a game? As we have discussed, your body can store enough glycogen to keep you going for a good amount of time. Unless you are doing a marathon or beyond, carb loading is not beneficial. In fact, because your body must store 2 to 3 grams of water for every gram of glycogen, you really are just weighing yourself down.
Even if you are an ultra-marathon runner, carb loading needs to be a very temporary thing. Remember that whole insulin-response business? Well, if you always eat tons of carbs, you always have elevated insulin levels. After a while, your body starts to ignore the insulin signals, leaving your blood sugar levels higher than they should be. So then you release MORE insulin, which your body eventually starts to ignore, and so on, and so on. This is called insulin resistance, and it is a sign that you are well on your way to type II diabetes. But don’t be fooled. You don’t have to be a carb loading runner to develop insulin resistance. Having a sugary Starbucks drink for breakfast? Maybe you have a white bread sandwich and some candy-like yogurt for lunch? Do you grab some take-out for dinner and a little icecream for dessert? So many people know what they should eat and think they are eating “pretty clean.” If you want to know for sure, start documenting every single thing you eat. You be surprised at the difference between perception and reality. I don’t want to be a downer, but I also don’t want you to develop diabetes. Just give it some thought.
Clearly, the preferred option is to focus on getting the majority of your carbs from complex carbs. This means upping your veggie intake (1 to 2 handfuls per meal) and easing up on pastries and sugary treats (like, maybe for special occasions). Of course, right now I’ll bet you are wondering how you will ever keep your 500g of glycogen topped off with only kale and broccoli. All right, fruits are OK too. But you really want to keep your veggie-to-fruit ratio around 5:1—lots of veggies, some fruit. IF you can handle it without putting on weight and are exercising regularly, you can also add in A LITTLE BIT of starchy foods like potatoes or rice. Ideally these are saved for AFTER INTENSE EXERCISE to help replenish those glycogen stores. If you are someone who gains weight easily, skip the starchy stuff and stick to the green stuff (meaning vegetables. What were you thinking?).
So, low carb or high carb? Let’s call this Controlled Carb. Most people can easily get all of the carbs they need from veggies and fruit. Start with 1 or 2 handfuls of veggies each meal and 1 or 2 pieces of fruit a day. But what if you want Froot Loops on your doughnut and icecream on top? Once in a while you just have to live. More than once in a while and you might not live as long as you were hoping. Track and monitor what you are eating. It won’t take long for you to find out if you really are eating “pretty clean,” or if you are actually full of carb.