"It's a complex issue that ... boils down to if you consume more calories than you burn, you put on weight," he continued.
He certainly seems to have a handle on the science.
So Coke is going to do something about this. It's going to produce more drinks in smaller bottles.
Psychologically, it seems likely to me that consumers will think that because something is in a small receptacle they can have more of it.
It is believed to be the reason fast-food franchises introduced dirt-cheap, mini-versions of their best-selling lines.
Soft-drink guzzlers will simply end up drinking more than they would have from regular bottles.
Coke will also make nutritional information, already on bottles and cans, more prominent.
And the people who ignore that information now will continue to do so in the future.
Coke will encourage you to exercise. The more exercise you do, the more calories you burn, the more Coke you can drink. Everyone wins.
Meanwhile, in Argentina, patron state of the ethically adventurous, Coke has done the unthinkable and launched a low-calorie version in a bottle with a green label instead of the traditional red one.
Is that colour ringing a bell? That's right - if it's in a green bottle it's obviously good for the planet, children's health, dolphins' digestive systems and puppies' coats.
And the bottles can almost certainly be recycled into the very softest onesies for unicorns.
The bottom line here is the bottom line. Coca-Cola's mission is not to stop you getting fat. Its mission is to make as much money as possible for its owners, and it can only do that in two ways: by charging more for what it sells at present, or by selling more of it.
If Fitzgerald isn't increasing his company's profits, then he's not doing his job, and he sounds like someone who is very good at his job.
Several questions have been on my mind this week:
When did Prince William start talking like Jamie Oliver?
Was there relief all around when the young prince arrived bearing absolutely no resemblance to James Hewitt?
Does not caring about how fast Kate will lose her baby bump make me a bad person?
And closer to home:
Has anyone ever actually seen Mr Fix-It, Stephen Joyce, fix anything?
Why didn't Ken Ring give Wellington a heads-up about its earthquakes?
Doesn't someone who is gullible enough to believe tap water causes leukaemia - because a bottled water salesman told them so - deserve to be taken for a ride?