Nothing about his eating habits was conveyed!

What if he’s one of those individuals that doesn’t like to eat in the morning and just heads out on his ride? He is after all 75 years old and only 175 pounds (don’t believe he conveyed his height, but 175 pounds doesn’t even leave a bundle of fat reserves). If he headed out without eating, pushing as hard as he did to achieve his 15 MPH average speed, he could easily have burned off his reserve from the meal the night before.

My friend doesn’t like to eat when he gets up in the morning, then wondered why he bonked an hour or so into our ride (and we push hard on our rides). He’s since realized the importance of eating prior to heading out for a long distance ride, so now he eats before the ride, even if it’s in the morning, and he’s been fine ever since.

Until more info is provided about his eating habits, bonking cannot be dismissed.