• a high carbohydrate training diet is a must to maximize muscle glycogen stores
• there may be a slight increase in daily protein requirements, but replacement needs can be met with 1 gram protein/kg body wt/day
• Caloric expenditures need to be consciously replaced to counteract the appetite suppression that follows from long hours of training
• a 3 day carbohydrate loading program gives an edge to muscle glycogen storage
• a 4 hour pre event meal should be utilized to top off glycogen stores
• some riders experience intestinal distress or symptoms of hypoglycemia if they eat in the 2 to 4 hours immediately before an event
• Calories must be taken during an event of greater than 2 hours duration - solid foods may offer some advantages in longer events which are done at slower paces minimizing the issue of delayed gastric emptying
• be particularly sensitive to fluid balance (loss vs replacement) as the risks of OVERHYDRATION increase with longer events. Don't forget to weigh yourself regularly during training as well as the event
• salt replacement beyond a normal diet (ie commercially available sports drinks) is important only under extreme conditions or in events lasting 8 to 10 hours or more

Recommended Nutrition Plan
The following comments are intended for maximizing glycogen stores for competitive events and long distance recreational rides. They are NOT meant as a general prescription for 1 to 2 hour weekend outings.

First, let's review a few basic tips that can be of benefit for your nutritional training program.

• Practice eating while cycling - your stomach needs to get used to handling food while exercising. You cannot "train" your digestive tract to get bigger or stronger, but you can define your own limitations and personal quirks before the day of the big ride.
• Don't switch fuels - stay with the on the bike foods you are used to eating.
• Make it simple for your digestive system - use processed breads rather than whole grains, liquids rather than solids, cooked vegetables instead of raw ones, and minimze fat.
• Don't fill up before the finish - anything you eat in the last 30 minutes will probably still be in your stomach, and if you sprint at the end might just end up coming back up.
• Train more - the best way to train your digestive system is to get in better shape. The closer you come to your VO2max, the more inefficient your GI tract becomes. So by raising your peak level of performance, you widen the range in which your stomach functions strongly.

Baseline Training Diet
(the weeks and days before the event)

• determine your daily Caloric needs as outlined in the section on energy requirements of cycling.
• calculate your body weight (BW) in kg (Wt in lbs x .455 = BW in kg)
• eat a baseline daily diet of:
• protein - 1.5 gm x BW in kg (multiply x 4 to get daily protein Calories)
• fat - 70 gm fat (the avg. American diet); at 9 Cal/gm = 630 Calories
• carbohydrates - the balance of your total daily Calories (total requirements as calculated above minus protein Calories minus fat Calories)as starches, etc.
• modify that diet for the specific periods noted below
• Pre-event interval (4 days to the event)
• During the event
• Post event

Pre-Event Interval
(4 days to the event)

• 4 days prior to the event
• 9 gm carbohydrate/kg BW/day (approx. 600 grams/day)
• limit exercise to minimum needed to maintain flexibility
• 4 hours prior to the event
• eat a 300 gm complex carbohydrate meal (rice, starch, pancakes, etc.)
• a high Caloric density glucose polymer sports drink may be ideal here
• define your own physiologic limits if you are accustomed to eating in the 4 hours interval before a ride - many riders get a psychological boost from eating a low fat meal or a liquid carbohydrate drink/gel during this interval (and as a bonus can supplement their internal glycogen stores for a ride of more than 1 to 2 hours)
• 4 minutes prior to the event
• 45 gm carbohydrate (fuel bar for example)

During The Event

• calories
• regular carbohydrate replacement - start immediately
• 60 gram of carbohydrate as a minimum per hour
• liquid preferred (i.e. sports drink)
• 10% concentration optimal (equivalent to a cola drink)
• start with half a water bottle (300 ml) in your stomach
• complex carbohydrate drinks permit additional Calories
• liquids
• 800 ml/hour (std waterbottle = 590 ml)
• drink at 10 - 15 min. intervals

Post Event

• 3 to 6 gm carbohydrate/ kg BW over the immediate 4 hours post event (100 grams per hour) - start immediately
• a high Caloric density glucose polymer sports drink may be ideal here
• protein appears to expedite glycogen replacement
• 600 gm carb/day for 2 days to optimize repletion of muscle/liver glycogen.

Source: Cycling Performance Tips