Today’s question is in answer to a statement often seen floating around on the internet: “All carbohydrates are just sugar.” Is this really true, though? And if so, then what does that mean for our health? Is it the sugar that makes some carbohydrates bad, or something else?
The question of the day comes from Cess.
Cess writes, “I’m still trying to understand why some carbs are so bad for us? Is it true that all carbohydrates are basically just sugar?”
If you have a nutrition question you’d like me to answer in a future episode, click here!
Are All Carbs Just Sugars?
In answer to this question, we need to specify what we mean by “sugars”.
In daily speech, when we talk about sugar, we’re talking about items like table sugar (sucrose), honey, and syrups like high-fructose corn syrup and maple syrup.
When we talk about “sugars” in a nutritional or biochemical sense, we mean the single-unit building blocks of all carbohydrates: Glucose, Fructose, and Galactose.
- Glucose is the most common carbohydrate, making up the majority of our carb-rich foods. Starches are chains of glucose units.
- Fructose is fairly rare, only being found in abundance in fruits.
- Galactose is basically found only in milk products (all milk, including mother’s milk)
All carbohydrates are formed of one or more of these sugars, primarily glucose.
How Complex Carbs Are Different than Simple Sugars
Complex carbs are chains of simple sugars, but just because they’re still formed of “sugar” doesn’t mean they cause the same problems as a diet high in simple sugar.
Complex carbs are generally formed of chains of glucose. Our digestive enzymes can only break the last link off the chain, so we can only release so much ‘sugar’ (glucose) at once.
Nearly all whole food carbohydrate sources store their carbs inside their cells, and cells have tough cell walls made of cellulose (an insoluble fiber) which our body must break apart in order to release the carbs within. This takes time as well.
In short, complex carbs introduce mechanical obstructions preventing too much sugar from being released all at once.
Our Body Absorbs Glucose and Fructose Differently
Another interesting aspect to how complex carbs and simple sugars affect us differently is the rate at which we can absorb the sugars contained within.
Our body can only absorb a maximum of 60 grams glucose per hour!
- Even if you ate 180 grams of glucose-only food, it would take 3 hours to fully absorb all the sugar into the bloodstream.
If you add fructose, then absorption increases to 90 grams per hour!
- This is 150% faster!
- Most foods are low in fructose though, or have mechanical obstruction like discussed above (fiber, cell walls, chains, etc.).
So What Makes Sugars Worse than Complex Carbs?
- Processed foods are digested quickly. Processing removes the mechanical obstacles which slow down digestion, like cell walls and fiber. It also renders large particles small, breaking the chains apart so there are more access points for our digestive enzymes to break down.
- Sugary foods are high in both glucose and fructose, increasing rate of absorption to 90 grams per hour, 150% faster.
Complex carbs are ultimately “just sugar”, but it’s NOT the sugar that is in-and-of-itself bad for us–it’s how fast that sugar enters our body! The faster it gets released, the worse its effects on health and weight!