Over the years I have learnt which foods work for me and which ones don't. However, I don't like the notions of "carbohydrate = bad" and "fat and protein = good" or you "must have carbohydrates for fuelling" or "a diabetic cannot train on empty". In my experience it isn't as simple as stuffing your face with carbs when racing or training or just living on salad.
Using training and some races to refine my fuelling needs and insulin requirements, the following will heavily influence my nutritional needs:
Pre-Race/Training - No to carb-loading
During training/ racing - No to gels or energy drinks
In most of my races, I am only required to take some fuel on 30-45 minutes into the bike leg (depending on distance of the race also in the second half of the bike). My prefered quick acting food is liquorice allsorts sweets (ca. 4gr COH per sweet). During an Olympic distance triathlon in September I took on 3-4 sweets (40km bike) at a glucose level of 112mg/dl which was at the start of the second of two laps on the bike. More below on this. I didn't take any food on during the 10km run that followed.
Post-training/race - inreased insulin requirements
Example: Olympic distance Triathlon and glucose levels
Wake-up: BS at 90mg/dl - I had a coffee with milk at 6:00 for which I set bolus and just nibbled on cheese and some almonds during the drive to the race venue. I try not to to bolus too much so that I don't have a lot of "Insulin-on-Board" for when the race starts to reduce risk of hypos.
I reduced my basal rate about 20-30min before the race starts to 70% (so 30% less of what I would normally have). As you can see I am happy to have levels go up to 180 which is what happened
During the race (start: 9:30):
The 1.5km swim in the lake took me just over 25 min; my glucose levels dropped a little but due to the intensity I knew they would not drop too much so that I got on to the bike without requiring food.
The bike was two laps totalling 42km which I completed in around 1:20hr. I did not take on any food until the start of the second lab where my blood sugar was at 113mg/dl: I took 3 liquorice allsorts gums (roughly equalling 12gr of carbohydrates). The rest of the bike, I completed without taking on anything else but water and (non-carbohydrate electrolytes) finishing with a level of 123 mg/dl.
The run was a muddy, off-road 10km trail run. The intensity was rather steady (with a lot of sliding in the mud trying not to land on my bum) and probably due to this, my glucose levels did not drop quickly which allowed me to complete the run leg in 45 min without the need of additional food and a finish level of 81mg/dl.
I had my basal rate set to 100% immediately but took a glucose tab once I finished (levels went to 70). Once they were back to 90 I increased the basal rate by 30% to 130% for 4-5 hours as from experience I have additional insulin requirements post-racing and levels tend to be elevated for a while. For lunch, I had a chicken salad so lot of protein and nuts as well as a coffee. Levels rose to 160mg/dl and remainded there for the afternoon which is why I keep my basal rate increased and carefully correct when necessary.
The bigger picture:
I would love to hear how you manage training and racing and what your approach is so please get in touch!