Apples contain a lot of fibers.
Don't eat wagonloads of appleseeds, each one contains a little bit of cyanide. This is done by the tree in order to spread its seeds. Our bodies and those of animals will more likely excrete the seeds and not digest them when they are a little toxic. The toxic is not digested but you should be careful with the consumption of crushed seeds.
The vitamin C content of apples depends on what kind of apple it is. Most sorts contain a lot of vitamin C.

1) Consume as much as you can of the 'right nutrition';
2) Avoid as much as you can of the 'wrong nutrition';
3) Exercise moderately;
4) Be happy with every small change you've been able to make permanently;
5) Don't make weight loss more complicated as it is.