Did you know digestion starts in your brain? Before your fork ever hits your mouth, your metabolism is already responding to what you see, smell, and anticipate.
Sometimes even just seeing food can trigger your brain to get saliva flowing—hence the term ‘mouthwatering.’
In today’s first clip of our new series, Ph.D. neuroscientist-nutritionist Anayanci Masis-Vargas walks us through what really happens when we eat carbohydrates—from first bite to blood sugar spike.
The Cephalic Phase: Your Brain Starts It All
The act of seeing, smelling, and even thinking about food triggers your digestive system to start preparing; this is known as the cephalic phase. It’s why chewing and being present while eating matter so much more than we’re taught.
Chewing = Chemistry
While the stomach primarily works on proteins, fiber, and fats, carbohydrate digestion kicks off right in your mouth with an enzyme called amylase. This enzyme starts breaking down the long chains of starch found in complex carbohydrates. The small intestine then takes over for further breakdown and absorption.
If food is ultra-processed or refined, like juice or those high in high-fructose corn syrup, you likely barely have to chew…and your enzymes barely have to work.
As Anayanci puts it:
"When something is so refined… we tend to barely chew it. But chewing is the first step in breaking down complex carbs into usable glucose."
These carbs absorb fast and can spike your blood sugar in minutes.
Why Food Combinations Matter
Your body digests carbs differently depending on what you pair them with. A piece of fruit with nuts or full-fat yogurt? Slows digestion and moderates blood sugar. But fruit juice on its own? Straight shot to the bloodstream.
“If you just grab the juice, with no fiber, no protein, no fat… then it goes straight to the intestine, absorbs, and reaches your bloodstream.”
Blood Sugar, Insulin, and Fat Storage
Fast-absorbing carbs lead to a rapid spike in blood glucose, which triggers a spike in insulin. If you're not active at the time, that glucose gets stored as fat.
“Insulin is the key that opens the cell to use glucose. If we don’t use it right away, we store it as fat.”
Why This Matters
We often think metabolism is about what we eat, but how we eat (and chew!) can significantly influence digestion, blood sugar response, and long-term health. Small tweaks—like slowing down, chewing more, and minimizing ultra-processed carbs—can make a big difference.
Understanding this fundamental journey of carbohydrates in your body is the first step toward making more informed dietary choices that support stable energy and your overall metabolic health.
🔜 Coming Sunday: How Cooking, Structure, and Macros Affect Absorption
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