Has anyone researched this and documented a correlation? I'm doubtful of your claims, and given your opening line, it's ironic that you go on to compare observations from your hobby against statements made by a doctor with 60 years of research behind him. His criticism is not unproven, there's no substantiation for that claim at all.
But you also make an interesting observation, if it has a basis in fact. It would seem to contradict the research of the Okinawan diet, which is almost exclusively plant-based, and 85% of calories are carb-derived.
Actually, a huge amount of archaeological research goes into trying to determine how we can tell what people ate from their bones, teeth, etc. The amount of information that can be gathered is pretty substantial. For example:
1) Tooth decay rates are still the largest indications of eating a carb-based diet. These are often also used as markers for cereal agriculture, naturally enough.
2) Societies that consume excessive quantities of milk develop bone abnormalities associated with anemia, because cow's milk interferes with absorbtion of iron.
3) Societies that consume lots of fish have bones that show up as a few centuries older when run through carbon dates. This is true both for consumption of salt-water and fresh-water fish.
The doctor is right about some things. A calorie is a calorie when you are looking at weight loss. A calorie in or out s a calorie in or out. But a lot of things impact how much energy we burn, and when we are hungry and these range from when and how long we sleep[1] to what we eat.[2]
Overly simplistic/reductionist approaches don't work.[3] Chemistry is not applied quantum physics even though our understanding of chemistry is informed by quantum physics. If you are trying to help people diet, arguing that calories are what you directly control rather than the end-game is just a recipe for misery.
[2] For example, the effects of what we eat on insulin production are well understood, but also there are effects of insulin production on appetite that are getting more attention now. See http://www.ncbi.nlm.nih.gov/pubmed/16933179 for example.
But you also make an interesting observation, if it has a basis in fact. It would seem to contradict the research of the Okinawan diet, which is almost exclusively plant-based, and 85% of calories are carb-derived.