Carbs are not the enemy.

Got it? Great! If you’re still around, let’s discuss this in more detail. Vegetables, fruits, and whole grains are primarily carb-based, and they’re the body’s primary fuel source. You can use fat and protein as fuel too, but they’re not as efficient for most bodily functions, particularly strenuous exercise and thinking. Anyone who’s ever “bonked” (ran out of blood sugar and glycogen) or hit a “brain fog” due to a low-carb diet knows this first-hand.

Dietary carbs also plays a huge role in micronutrient absorption. They shuttle in water-based vitamins including C and the B complex. Also, many carb-based foods contain the vitamins, mineral, and phytonutrients mandatory for good health.

Where you get into trouble with carbs is when you have too many of them or you eat poor-quality ones. Think of your body as a Formula 1® racer, and think of carbs as gasoline. If you put cheap gas in a race car, your engine pings and you can’t go as fast, right? Now, let’s torture the metaphor a little and say that it’s a magic Formula 1 racer, and that when you pour too much gas into the tank, it converts that fuel into extra upholstery. So, if you add the perfect amount of quality gas, your car performs really well. However, if you add too much gas, your seat starts to swell, you can’t fit in your jeans I mean, you can’t fit inside the car, you can’t steer properly, and everything goes to pot.

So the trick is to eat healthy carbs in the right amount.

A tale of three sugars.

Carbohydrates are broken down into three groups based on how complex they are molecularly. Simple carbs are also called “sugars” They contain one or two molecules. Complex carbs contain multiple molecules, but can still be broken down by the human body. Fibre is so molecularly dense that we can’t break it down, so it passes through us or, in some cases, it’s broken down by bacteria in our intestines.

As they pass from the mouth through to the intestines, both simple and complex carbs are broken down into a single molecule carbohydrate called glucose, or blood sugar. That’s our body’s primary fuel. It’s also stored in muscles and the liver as glycogen, a quick-release emergency fuel supply.

Say no to blood sugar spikes!

If you end up with too much glucose in your blood, it causes something called a blood sugar spike. Your pancreas then releases a hormone called insulin that converts excess glucose to adipose tissue, or body fat. In moderation, this is just a normal function of the human body, but if you’re constantly experiencing blood sugar spikes and overworking your pancreas, eventually, you can develop something called insulin resistance, where the insulin receptors in your cells have a hard time recognizing insulin. This can lead to diabetes type 2, where your body can’t process glucose properly.

The trick to avoiding blood sugar spikes is to be smart about your carb intake. Technically, the simpler a carb, the faster we absorb it, but avoiding simple carbs in favour of complex carbs doesn’t prevent blood sugar spikes. There’s been a lot of press about the evils of refined (or added) sugars. They are indeed evil, but not necessarily because they’re simple carbohydrates. The Glycemic Index (GI) rates how fast foods are absorbed into the body. This absorbability is based largely on carbs. You’d think that simple carbs, because they break down easier, would categorically have a higher GI number, but this isn’t the case. Refined (white) flour is comprised of 100% complex carbs, yet that puffy, white sandwich bread you might have loved as a kid has through-the-roof GI ratings. Furthermore, most fruits and veggies, where you should be getting the lion’s share of your carbs, contain a mix of simple and complex carbs.

The trick to healthy carb consumption isn’t to avoid sugars, but to avoid added sugars (most of the time) and to make sure your carb sources are rich in fibre. Because the human body can’t absorb fibre, it slows the absorption of everything eaten along with it. Those aforementioned fruits and veggies are, usually, loaded with fibre, which means they absorb slower than soda, corn chips, or candy, which contain no fibre at all.

Protein and fat can also slow absorption, but not as well as fibre.

Speaking of protein and fat . . .

I know what you’re going to ask. If protein and fat can be converted to glucose, why not skip carbs entirely?

First off, when you drop your carb intake down, you’re most likely dropping your intake of several key vitamins, minerals, and phytonutrients.

Secondly, the conversion of amino acids to glucose gluconeogenesis isn’t terribly efficient. Dietary fat can also be converted to glucose, but it’s a complex process. Triglycerides are an important energy supply, but they work much better in tandem with carb intake.

And when you’re a serious exerciser, your need for fuel increases all the more. When you don’t have enough glucose in your system, the first place your body looks to for energy is glycogen that emergency fuel source we discussed earlier, so if you eat a low-carb or a severely low-calorie diet, your glycogen stores tend to be perpetually low. Any prolonged, serious physical effort requires adequate glycogen. When you have less of it, it impairs performance.

In fact, exercise is one of those rare times when you actually may want to replenish blood sugar and glycogen as fast as possible using straight sugar. This is particularly true after an intense workout lasting an hour or more. If you’ve tapped your muscle glycogen and blood sugar, then a recovery drink or snack with a ratio of between 3:1 to 5:1 simple carbs to protein (and no fibre!) will recharge that glycogen quickly while transporting the amino acids to the muscles to accelerate the recovery process.

As I mentioned earlier, if you’re on a particularly low-calorie or low-carb diet, those glycogen stores may deplete in less than an hour. If you’re barely making it through, say, the 30-minute version of an INSANITY class, you can try to solve the problem in the short-term by using a recovery drink, but in the long term, you’re better off increasing carbs in your overall diet.

How many carbs do you need?

There’s no set number. It varies massively depending on the individual. Heavy exercisers generally need more than light exercisers, by virtue of the fact that they burn more energy. Most athletes should make sure that upwards of 50% of their total calories come from carbs.

The great thing about this particular macronutrient is that it’s extremely self-regulating provided you’re getting it from healthy sources. Because of the fibre in produce and whole grains, they tend to be filling, so you get full before you overeat. The problems occur when you’re eating refined carbs, including added sugars, sugary drinks, and juices. The various bodily functions that control satiety don’t know how to regulate these types of food, so overindulging is a recipe for weight gain and other complications. And an increasing body of science is linking excess added sugars to an assortment of issues, including heart disease and cancer.1

So a simple rule is to avoid added sugars if you don’t know how to manage them in your diet.