How long does it take to realize it's working?

I'm lazy I'll admit it. Recently I decided I wanted to do something about being unhappy with how I look instead of just saying it. I'm sadly easily discouraged, I've been working really hard at losing weight. I use half or most of my lunch each day at work and I haven't noticed anything. I want to boost my metabolism and be healthy. Other than doing aerobics and counting calories what do I need to do to see changes?