There is also a big physological difference between the amature and the elete professional athlete and so the answer is really different for each individual and it also depends on fitness levels and training schedules so one size really does not fit all.
Good healthy eating guidelines
Before a ride
During a ride
Gels mainly contain glucose with no nutitional value (sometimes added caffeine too) this is all absorbed straight into the bloodstream being single molecules which elevates the levels insulin and so the sugar can then get stored as fat. A mix of simple and complex carbohydrate are best to deliver optimum energy and nutrient levels like fresh fruit, cereal bars etc.
After a ride
Post ride meal example: poached egg with salmon on wholemeal bread and a glass of fruit juice contains everything you need and is natural!