Bananas are the best natural way.
Also, get up early and eat Porridge with honey, releases energy slowly.
When watching the pros, although they eat gels etc, they eat constantly and drink all the time small sips.
That is to avoid a hunger flat which is basically when u run out of juice the body can draw on.
I prefer natural food and fruit but thats just me.
Also, on hot days, very cold water may feel good but draws down a lot of energy as the body has to warm it up to core temperature. Best drink is room temperature drink or if cool is needed, take 2 drink bottles, one frozen solid and one cool, so as one empties, the other starts to thaw out.
Remember, lots of little sips are the go.
Stay up right guys.
I can't eat bars that contain oats, they just clag up in my mouth so i use Be Natural Nut Bars. Winners Gels as others have suggested, and they are reasonably priced and frankly taste less objectionable to many others, none that I have tried are really enjoyable. I like snakes and similar lollies but Glucojels are acceptable and I'm told they are much better. Bellis apricot bars or similar generic brands are easy to carry and easily digestable. If I'm going for a 100km plus ride I make a point of stopping at least once at a supermarket and buying a banana or two what ever the price and Sanitarium Up& Go choc milk.
Chilled water, nice for the mouth but bad for the gut and the body.
This discussion has been up before and if you do a search you will find a lot of info including some well researched info from DahonDude.
+1 for the winners bars. Particularly the Apple Berry Crumble bar. It doesn't deteriorate in your jersey pocket like a lot of other things (e.g. Bananas, some muesli bars, etc). Not a big problem this time of year but summer can mean hot mushy food if you don't choose correctly.
I'm a fan of Gels, but for most rides (all bar racing or high intensity training) I'd stick with real foods. There is possibly a case for a carb drink (I carry a smaller 500ml carb drink (High5)) on the longer rides. You can have a swig when you start to drop off. Best to hold in your mouth for a few seconds. There are studies that show this can provide an instantaneous lift, but thats another post all together.