If you eat 100 calories a day more than you burn you will put on about 10 lbs in a year. There about 100 calories in an apple.
Doing exercise is great but sorting out your diet is key.
A cup of coffee with sugar and three chocolate biscuits is about 300 calories. To burn this off you will need to cycle for at least half an hour.
I use an app call MyFitnessPal, which makes calorie counting very easy. It really opened my eyes to how bad some foods are, and has helped me make more informed food choices.
One of the biggest shocks was white bread, each slice is about 100 calories.
Here's an example of how bad bread is.
2 homemade bacon and egg muffins and a cappuccino over 800 calories.
2 eggs, 2 bacon, 2 sausages, baked beans, mushrooms and a cappuccino just over 700 calories. A lot more food but less calories.
Don't worry I don't have this everyday or even every weekend but you need to have treats.
Slimming World and Weightwatchers points systems will give you the same feedback, but the app works best for me.
Find what works for you and use it, the weight will drop off when you make some small changes. Go out cycling couple of times a week and you will be hitting your goals.