I'm not obese. I have a family history of obesity. On the contrary, I am a bit underweight, and I have tried very hard to gain weight and have never managed to accomplish much. What are obese people eating that I'm not eating? What foods are high in soybean oil?
Have you ever kept a log of the food you eat in a day? Admittedly I come at this from a very different perspective being obese, and having been much more obese in the past, but actively logging my food and retrospectively calculating calories gave me a much better sense of how much I was actually eating.
When you've recorded some data on that it would be productive to calculate your basal metabolic rate, which are the calories your body uses on the daily (so any exercise adds on to that). Comparing those two figures might be productive.
Of course there may be genetic factors going on but perception is so powerful it's the first thing I'd question