cartsman wrote:
Personally I take the view that there's not much to choose between the brands, and I go with whatever the on-course nutrition is. Figure the benefit of not having to plan and carry all my nutrition outweighs any benefit that one brand offers over another.
The key is getting the mix of solids, liquids and concentrations right. And that varies a lot depending on distance, weather and individual. On a hot day I need a lot more fluid than on a cool day, so either I need a more diluted concentration, or I need to drink bottles of straight water alongside the energy drink. On hot days I also find I have less tolerance for solids so prefer to get all my calories from liquid. Distance impacts me as well. 70.3 I don't need a lot of extra calories to get through the day, so can play it pretty safe and get through on 200-250/hour which is unlikely to cause GI issues. For IM I need to push the envelope and get the calories in at a higher rate, which leaves less room for error if I don't get the right amount of hydration in. I don't run well if I've taken solids within ~2 hours of running, so on 70.3 I tend not to eat anything solid. But IM is too long a day to go liquid only, so I'll use the first half of the bike to get some solids in.
I think the key things to figure out and practice are:
- Your calorie burn rate, which you can estimate reasonably accurately from a HRM/power meter that knows your zones, weight, etc
- Expected finish time for your distance/fitness
- Above 2 factors will enable you to estimate how many calories you need to take on during the race. As a starter for 10 assume you have 1500 cals of glycogen stores when you start the race, and you get 50% of your calories from fat. E.g. if you're burning 800 cals/hour and your expected finish time is 6 hours, then you need 4800 calories to get through the race, of which 2400 will come from fat and 1500 will come from pre-existing glycogen stores, leaving you 900 calories to take on. That's 150 cals/hour. There's some estimates in there and you don't want to finish with the tank completely empty, so up that to 250 cals/hour and you should be in the right ballpark. Do your own calculation, then practice and refine as necessary
- On top of the above, you need to get a good feel for how your sweat rate varies in different conditions, as that determines how much fluid you need to take on along with those calories. You can weigh yourself before and after training, pee colour and how much fluid it takes to fully rehydrate after training will also inform this. The more you're sweating, the more you need to think about replacing lost minerals either via drinks with electrolytes and/or salt stick
- Everything after that is personal preference - whether you prefer gels, liquids, solids, what flavours, etc
seems like I need more than 400 cal/h for a 9.5 hours IM. That is the problem))))