I've read my share of self-serving surveys, and may I be at least the second to commend the Food Standards Agency on its latest contribution to the genre. This one found - quel surprise - that eight out of 10 cats prefer the FSA's traffic lights.

I'm being glib, I know. I'm quite sure that shoppers find traffic lights useful, just as I'm certain shoppers also find GDAs informative. But so what? As I've noted before, in this column, events in Europe are even now overtaking the parochial, macrobiological machinations we've got embroiled in. But the debate - on both sides - should never have been framed in terms of colours or percentages of either notional portion sizes or the equally random 100g measure. It should be faced off in the cold hard currency of calories; of energy out and energy in.

And a look at the new and absurdly moreish pouch of Cadbury Clusters I purchased confirms this. Would a red for sugar on the Clusters bag have been any more informative than a GDA panel telling me that a 25g portion contained 17.2% of total daily sugars and 17% of fats? Far more useful would be a glaring graphic telling me that if I scoffed the lot I would be consuming 700 calories.

The reason people become obese is not because they choose pork pie instead of tossed leaves with a Caesar salad dressing; or a 25g portion of Cadbury Clusters over a nut cutlet. It's because they eat too many pork pies; have too large a portion of Caesar salad dressing; eat whole pouch packs of Clusters and allow their diet to become not just unbalanced but overly calorific. A recent scientific study found that if you give someone a bigger portion than they need, they will eat it. Again, obvious. (You only need to visit a restaurant in the US to understand why Americans are so fat). Unfortunately, you won't find portion control underpinning government policy right now. It needs to.