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Nicole Moore Master Nutrition APD

Finding your carbohydrate tolerance

It's important if you have pre-diabetes or type 2 diabetes that you determine your carbohydrate threshold. Many patients ask how many carbohydrates they will be able to eat in the long term to keep their blood sugar levels in a healthy range, and to keep their weight down. 

My answer is simple: everyone is very different. Everyone will tolerate a different amount of carbohydrate and have different carb thresholds or tolerance. So, how do we establish what our threshold is?

How to calculate carbohydrate tolerance 

"Tolerance level" is the amount of carbohydrate you can eat before your blood sugar levels start spiking and you gain weight. If you overindulge in carbs, (as we often all once did), you might also experience other symptoms such as tiredness, hunger and fogginess. 

Some people can tolerate 50 grams of carbohydrate per day (such as a bowl of spaghetti). Others may tolerate up to 100 grams per day (think two sandwiches or a large portion of rice). Yet others may only be able to consume 25 grams of carbohydrate per day (such as half a burger bun).

It's important to figure out the correct carbohydrate formula for you. How much carbohydrate can you eat each before it starts impacting your health,  you gain weight and your blood sugar levels spike sky-high?

The first thing to do is to work out how much total carbohydrate you're currently eating. We do this by calclating the average total carbohydrates in all the foods and fluids you eat each day. You need to become a carbohydrate detective! We recommend referring to the Defeat Diabetes carbohydrate food list so you can get a good idea of how many carbs wind up in your tummy each day.

Next, measure your fasting blood sugar levels in the morning, before you start eating for the day. Measure this every day for a week so you can determine your average fasting blood sugar levels.

Finally, I suggest you aim to go on a low carb approach diet of 50 grams of carbohydrate per day. This will lower blood sugar levels on average over time and give you a benchmark to use as a measuring tool. 

Once you've been following 50 grams of carbohydrate per day for at least three weeks, or until your high blood sugar levels are reduced closer to a healthy fasting range of between 5-7 mmol/L, you can then start adding carbohydrates to determine how much you can tolerate before your blood sugar levels spike again.

For example, if you eat 50 grams of carbohydrate per day for a few weeks and your average blood sugar levels drop from 8 mmol/L to 6 mmol/L, fasted, you can slowly add more carbohydrate to your diet. You might increase to 70 grams per day then 80 grams, then 100g per day, to determine how much carbohydrate you can safely eat before your blood sugar spikes to 8 mmol/L again.

Once your blood sugar levels have spiked you have reached your carbohydrate threshold or tolerance levels. You now know how many carbohydrates you can have before your blood sugar levels reach unacceptable levels, and so how many grams of carbohydrate you need to stick to per day.

This is powerful information to have and will allow you to manage your type 2 diabetes, as long as you don't exceed your carbohydrate tolerance!

In summary

  1. Everyone has a different carbohydrate threshold or tolerance level. We can all eat different amounts of carbohydrate before our blood sugars start to rise and our pants get tight, and we experience gastrointestinal symptoms such as bloating, tiredness and fogginess.
  2. To work out your carbohydrate tolerance or threshold level we recommend you start tracking how many grams of carbohydrate you're eating each day and what your current average fasting blood sugar level is.
  3. You might consider a low carb intake of 50 grams of carbohydrate per day until your blood sugar levels drop to a lower and healthier range.
  4. Then slowly start adding more carbohydrate back to your diet. Once you see your blood sugar levels spike and/or your weight going up this is your threshold or tolerance level. You now know how much carbohydrate you can tolerate. 
  5. You need to become a carb detective using the Defeat Diabetes carbohydrate food list to calculate how much carbohydrate you're eating each day. 

Improving our blood sugar levels and weight to defeat diabetes is determined by understanding how much carbohydrate and sugar our bodies can tolerate and knowing our carbohydrate threshold.

Join Australia's first evidence-based and doctor-led program transforming the health of Australians. Download the Defeat Diabetes app today.

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