When it comes to endurance sports, performance is powered not just by training, but by how efficiently your body absorbs and uses fuel. At the heart of this process are two key transporter proteins in your small intestine: SGLT1 and GLUT5. Understanding how they work can help you create powerful, homemade sports nutrition products using only ingredients from your local supermarket.
The Science of Carbohydrate Absorption
SGLT1: The Glucose Transporter
SGLT1 stands for Sodium-Glucose Linked Transporter 1. It is located in the lining of your small intestine and is responsible for actively transporting glucose into your intestinal cells. This process requires sodium, which acts like a key to unlock the transporter. Without sodium, glucose absorption is significantly reduced. This is why sodium is a critical component in sports drinks.
GLUT5: The Fructose Transporter
GLUT5 is a different transporter that handles fructose. Unlike SGLT1, it does not require sodium and works through passive diffusion. It allows fructose to enter intestinal cells through a separate pathway. This is important because it means your body can absorb more total carbohydrates when both glucose and fructose are consumed together.
Why Use Both?
When glucose and fructose are consumed in a 2 to 1 ratio, they use separate transporters, which increases the total amount of carbohydrate your body can absorb per hour. This dual-pathway strategy can deliver up to 90 grams of carbohydrate per hour, reduce gastrointestinal discomfort, and improve endurance performance.
DIY Sports Nutrition Using Supermarket Ingredients
You do not need to buy specialized powders or syrups to benefit from this science. With a few common ingredients, you can make your own high-performance sports drink and energy bar.
Homemade Sports Drink Recipe
Makes 1 liter
Ingredients
3 tablespoons honey (alternatively, use agave syrup which is even higher in fructose)
2 tablespoons rice syrup
1/4 teaspoon table salt
50 milliliters lemon juice
Water to make 1 liter
Instructions
Mix honey, rice syrup, and salt in a small amount of warm water to dissolve.
Add lemon juice.
Top up with cold water to make 1 liter.
Shake well and chill before use.
Why it works
Honey provides both glucose and fructose.
Rice syrup is rich in glucose.
Salt provides sodium to activate SGLT1.
Lemon juice adds flavor and vitamin C.
Homemade Energy Bar Recipe
Makes 4 bars
Ingredients
50g honey (alternatively, use agave syrup which is even higher in fructose)
2 tablespoons rice syrup
50g cup chopped dried dates
70g cup rolled oats
50g cup puffed rice (you can also crush rice waffles)
2 tablespoons almond butter
1/4 teaspoon salt
Optional: lemon zest or vanilla for flavor
Instructions
Warm honey, rice syrup, and almond butter until soft.
Mix in oats, puffed rice, dates, and salt.
Press into a lined tray or freezer bag and refrigerate until firm.
Cut into bars and wrap individually.
Why it works
Honey and dates provide both glucose and fructose.
Rice syrup boosts glucose content.
Salt supports glucose absorption.
Oats and puffed rice add texture and slow-release carbs.
Final notes
You can replace honey for agave syrup which is even higher in fructose. Agave syrup contains 70–90% fructose, while honey contains ca. 40% fructose. I tested both recipes during a 3-hour bike ride and a 30-minute rowing workout. During the biking I ate a total of 3 bars in the last two hours. During the rowing I only consumed the sports drink. Both worked well for me. I bought all ingredients at dm in Germany (https://www.dm.de/), but you can find these ingredients also in other larger supermarkets. One bar and one liter of sports drink cost less than 50 cents.