Personally I think that focussing on calories is the wrong way to look at the all obesity epidemic.
What should be tergeted is junk food, food that is harmful and addictive and leads to diseases, including obesity, diabetes, heart disease and cancer.
Healthy food is unlikely to make you obese... if you eat the right amount of fibre, so unprocessed food, you will feel full before you eat too many calories. The problem with junk food is that it is calories dense and fibre poor, so in order to feel full, you end up eating too much. of it
We didn't evolve to eat calories dense food. This is the real issue... any other attempt only targets the symptoms, but not the root of the problem.
More fruit, more vegetables, more whole grains... fewer sugar/protein/fat packed processed crap