There are lots and lots of articles on what you should eat while riding. Some of those articles may even give you an idea of what not to eat on a ride, but with few specifics. Here is your chance to read about five things definitely not to eat on a ride and why they could ruin your day.
The 5 Things Not To Eat On A Ride
Meat
Most of the digestive issues from the foods on this list is about their basic digestibility. If it takes a long time to digest, a food will not provide much benefit during a ride; you will not have access to the macro nutrients by the time your ride is over (unless you are on an epic ride). Meat tops the list as slow to digest. It requires lots of mechanical digestion, hence energy that could be going to your legs, along with the blood powering your stomach. Low carbohydrate content means very little quickly available energy during your ride. Save your meat for post-ride recovery.
Ice Cream
Ice cream has a bit more accessible carbohydrates than meat, but suffers from the same lack of digestibility as meat. What ice cream (and dairy in general) has over meat is its ability to produce greater quantities of flatulence. You do not want that in your chamois. Most people have difficulty with lactose, whether they know it or not, and you may get a surprise grumble after a milky treat.
Gels and High Sugar Drinks
Surprise! Gels and other high sugar sports drinks only serve to dehydrate you, despite the claims on the packaging. Read the fine print on a gel and it says you should consume with a full bottle of water. How are you going to carry that many bottles on a long ride.
What happens is that the sugar in the gel or drink needs to have a lower concentration for your body to absorb it. That additional fluid to dilute the sugar solution comes from the fluid you already have in your body. Blood viscosity goes up and performance goes down.
Stick with solid food that is has a relatively high carbohydrate content. Solid food will rely on mechanical digestion versus dilution of a sugar solution. You will perform much better.
Spicy Food
Avoiding spicy food is pretty simple. You do not want it to repeat while you do your repeats. More powerful than a power meter or heart rate monitor to know if you are going hard enough is the old throw-up-in-your-mouth. It is bad enough to regurgitate; you do not want it to be spicy too.
And spicy food can cause a bit of stomach discomfort, but that is not the main point here.
Raw Veggies
A few carrots sticks or a small salad will be fine during the course of a ride, say on a lunch stop, but it is not going to give you a boost in energy levels. If you do find the most delicious broccoli on your ride, maybe when stopping at a farmers market?, try to avoid gorging on it. It is going to be tough to digest, along with probably giving you an extra blast out of the old jet exhaust. You may also find the blood draining from necessary parts of your body like your legs and head to power the digestion of all that fiber.
So What is Left to Eat?
There are still lots of great options to snack on while riding. Based on the above, you should be able to distill that your food should be solid, digestible and have a high carbohydrate to protein and fat ratio. Eat what you think is delicious and maybe error on the side of bland to avoid the reflux. You will be more likely to enjoy your snacks and stay fueled properly for your ride.