I was diagnosed with T2 just over 6 weeks ago. Went on low carb shortly after, 50g carb per day limit to start, but quickly down to 20-30g keto territory. I'm currently managing with diet and lifestyle changes, no medication.
I can only speak for my own experience and 6 weeks worth of data, but low carb/keto with exercise has:
- Allowed me to lose 2st 2lb since diagnosis (quite a bit of water weight loss in that to be fair, plus I'm very overweight), with very little hunger.
- Reduced my first morning fasting BG reading down from 15s at the start, to 6s for 2-3 weeks consistently now.
- Reduced my pre-meal BG readings down from 15s at the start to 5s consistently for 2 weeks now.
- Reduced my 2hr post-meal readings down from 17s at start to 5s or 6s for 2-3 weeks now.
- Reduced my average resting heart rate from 90-100 bpm at the start, down to 70-80bpm in the last 7 days.
- Reduced my average 7 day blood pressure from 134/94 at the start, to 121/79 in the past 7 days (same medication levels, no changes).
- Triglycerides have reduced from 5.3 when first diagnosed, to 2.5 as of last blood test 3 weeks ago. Still high, but that was achieved in 3 weeks of low carb/keto and exercise.
I've been very strict on this diet, no alcohol, never exceeding 30g of carbs in the last 4-5 weeks, and mostly being in the 20-25g range for carbs per day on average.
In my experience at least, low carb and keto aren't magic diets, as you'll see some proclaiming on other platforms. It can be challenging and very restrictive, but the results above outweigh all of that for me. Its effect on BG levels, in particular, allowed me to quickly control and resolve many high BG issues, e.g. unquenchable thirst, frequent urination, slightly blurred vision - possibly not relevant to prediabetes, but worth mentioning just in case. If the person in question can control their carb cravings, I'd recommend it, even if they don't go to the keto end of carb restrictions and just maintain a simpler lower carb approach than they do at present, with better quality carbs chosen for those they do consume.