GLPs and Carbs: Why "Low Sugar" Can Be Misleading
Graham Phillips
FRPharmS • Founder
Key Takeaways
Don’t rely solely on calorie counting
Focus on nutrition quality to protect your muscle and bone health
Work with a healthcare professional to monitor your progress and avoid complications
A lot of people using GLP-1 medications (like Ozempic, Wegovy or Mounjaro) believe they’re doing well as long as they avoid sugary foods and counting calories
But here’s the problem:
You can have a “low sugar” diet but still be eating loads of carbs… and your body turns those carbs into sugar anyway.
Let me explain.
What actually happens when you eat carbs?
Most carbs (especially refined or starchy ones like bread, pasta, rice, potatoes, breakfast cereal) are long chains of glucose molecules “holding hands” held together with an oxygen molecule in between. So the moment you eat them, your digestive system breaks them down into simple sugars (mainly glucose) often faster than table sugar itself.
For example 2 slices of whole-wheat bread = about 6 teaspoons of sugar in your bloodstream.
(Yes, really — that’s based on glycaemic index testing!)
This is the key point:
- Carbs are just sugar in disguise.
- Your blood sugar rises sharply after eating them.
- Your pancreas releases insulin to bring that sugar under control.
OK, so what does insulin do?
Insulin’s job is to:
- Move glucose into your cells so it can be used or stored.
- Lock your fat stores so you can’t burn fat easily.
So when insulin is high:
- Your body can’t access stored fat for energy.
- You’re more likely to store fat, not burn it.
- And once blood sugar crashes down again, you feel hungry, often craving more carbs.
This is sometimes called the “blood sugar roller-coaster”.
Right but I’m on a GLP-1, so why does this still matter?
GLP-1 medications help by:
- Slowing stomach emptying
- Reducing appetite
- Flattening post-meal glucose spikes
But they don’t cancel out the metabolic effects of a high-carb diet. If you’re eating lots of refined carbs, you’re still triggering insulin surges, blocking fat-burning, making it harder to lose weight and more likely to feel tired, sluggish, or hungry again soon after eating.
OK so now let’s turn to Dr David Unwin’s sugar equivalence charts.
GP Dr David Unwin has become well-known for translating the glycaemic load of everyday foods into “teaspoons of sugar”.
For example:
Food (typical portion) Teaspoons of sugar equivalent*
Baked potato (150 g) 8 tsp
White rice (150 g) 10 tsp
Whole-wheat bread (2 slices) 6 tsp
Breakfast cereal (40 g) 9 tsp
Banana (1 medium) 5 tsp
These visual tools help people see that even “healthy carbs” can act just like sugar in your body.
So what can you do?
If you’re on a GLP-1 medication and want the best results:
- Focus on low-glycaemic, whole foods
- Cut back on refined carbs and starches
- Prioritise protein, fill up with healthy fats, minimise sugar and carbs
About Graham Phillips
Graham Phillips is a registered pharmacist (FRPharmS) with over 35 years of experience. Frustrated by “pill for every ill” medicine, he founded ProLongevity to help people reverse chronic disease and lose weight through precision lifestyle medicine.
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