You've made the switch to healthy cooking — olive oil instead of butter and whole grains instead of processed carbs — but you're not losing weight. Even if you're loading up on tons of healthy food choices, it won't matter if you are consuming tons of calories.
The best way to make sure you're eating appropriate serving sizes is to be scientific about it. Keep measuring cups and spoons handy when it comes to everything you prepare. Don't just eyeball a half a cup of granola or freely pour marinara sauce over your pasta. Chances are you'll overestimate and not even realize you're eating half a cup of almonds instead of a quarter cup serving. The same goes when you're cooking. Measure out two tablespoons of olive oil instead of just pouring it from the bottle. If you have items that are difficult to measure, such as meat, chicken, or fish, use a food scale instead. You don't have to be anal about it, just be aware. The extra small amounts of food you eat over time really add up, so if losing weight is on your mind, use measuring cups every time you eat.