fergusc
That's it exactly for type 2's - biochemically, carbs burn more easily than protein or fats-but the body can make use of each pathway, so that shouldn't be the main contributor unless one or more pathways are totally broken.
There are 4 major receptors for taste on our tongues- sweet, salt, bitter, sour. I used to do a little genetics experiment when I was a high school teacher- I gave the kids a PTC paper to chew up (it's bitter- like aspirin) - most of them would gag and go running for the water fountains- but some of them (non-tasters) would chew that paper like bubble gum and look at their classmates like they were nuts- when I sent the papers home the non- tasters all had parents who were non- tasters too. We would also do tongue mapping of receptors- where kids would paint different liquids (sweet, salt, bitter, sour) on the tongues of their lab partner- and map out the locations of the different receptors. Some kids appeared to have larger numbers of receptors for certain tastes than others. Maybe your roomie inherited an abnormal amount or type of sweet receptors.
Evolutionary biologists contend that the pattern and number of individual receptors in a given population correlate to the environmental conditions present- so a population that lived in a desert area for example would have a greater number of sweet receptors for that rare time when fruit was available. It's not easy to prove contentions like that- so I generally don't give those sorts of hypotheses much weight. But who knows?
It's only recently that 'Americanized' diets have proliferated, but wherever they go, obesity and diabetes follows. High processed carb consumption, high sat/trans fat consumption and decreased levels of activity seem to be the major contributors to me. One of my fellow grad students was from India- he gained 30 pounds and had elevated BP, BG and lipids within a year of arriving. His wife had a baby and his mother came from India for 6 months to help them out. She cooked only traditional foods for them- he lost 40 pounds, all of his numbers dropped back to normal - he was far more pleasant too. The diet was hugely carb, high in fat, and mostly vegetarian- but nothing processed.
I think that, anecdotally at least, both genetics and environment combine to contribute to our health woes- but it's hard to quantitate because people are not genetically identical Sprague-Dawley lab rats!
sandy