There has been alot of interest regarding nutrition for Ironman so here are some simple thoughts and ideas.  Please remember that everyone is different and these are general guidelines.  Also remember that it is extremely important to try out everything beforehand in training.  Your long bike and run days are ideal opportunities to practice exactly how you are going to race.  Practice, practice, practice so your body knows what to expect.
The key really is consuming enough for your own body type and size.  I go on a simple rule of about 1.5-2 grams of carbohydrate per kilogram of body weight per hour.  So, I am 60kg which means about 90g of carbs per hour.  This equates to a bottle of sport drink and about 11/3 gels per hour.  It’s very simple math and the carbs can be attained in pretty much any way you are most comfortable with, this is why it’s important to try it in training first.  You can use gels or bars or liquid only.

Fluid I consume 1-1.25 liters per hour depending on the temperature and I am usually drinking sport drink in Gleukos or from the aid stations.  Remember that this accounts for some of your carbohydrate intake.  I also take some water at every aid station just to have a bit of a top up.  I would suggest 1-1.5 liters for sure

Sodium is another factor to consider and you can get it in a variety of product.  Salt Stick brand is really good.  you need 500-1000mg per hour when you get over 4 hours and this can be consumed in pill form that you carry or you can dissolve it in the liquid in your bottles.

Remember that there are aid stations very regularly so don’t panic, you will never be long without food or drink, but also remember that you can overdo it.  The body can only process so much at one time so you have to go in with a plan.

Pace your food intake.  I drink every 5 minutes and eat every 15 minutes so i never have to dump huge quantities of sugar into my stomach at once…..little bits at at time the whole day is the best way to do it.

Know what is on the course and practice with that.  I choose Gleukos as my main drink when I have the choice but at most Ironman races including Canada, Gatorade is the primary sponsor so get used to it.  PowerBar products will also be on course as well as cookies, bannanas and cola of some sort on the run.

Liquids are more easily digested than solids but also very important to remember that caloric and carbohydrate needs are met through liquids so factor those into your calculations.

Start out with your own bottles and two should be enough on your bike.  Remember that liquid weighs alot and IM Canada is hilly!

On the run you can wear a fuel belt with your own nutrition but there are aid stations every mile.

Practice, practice, practice!