In these days of sharply contrasting seasons, we're soon going to start paying more attention, I'm sure, to eating food that is appropriate to the time of year. After all, we are becoming more sensitive to the vagaries of climate in other ways. Seasonal affective disorder (Sad) has, I've noticed, become virtually ubiquitous as an excuse in recent years. Otherwise rational adults use it to account for all manner of failings, from the personal ("Honestly, I do like you. It's just that the weather is playing havoc with my hormones") to the professional ("I would have filed that review/turned up for work/ kept that appointment, only my Sad has really started to kick in"). The weather's power to affect us has been especially evident during the recent heatwave, which has turned most of us into dazed automatons and has, for some reason, caused public transport to become even less reliable than usual. Global warming, it seems, is making Sad sufferers of us all.

These days, if the experts are to be believed, most physical and emotional problems (whether obesity, ADD or depression) have some sort of dietary cause - or at least can be tackled by dietary means. No doubt this will prove true of Sad as well. I expect that, as I write, nutritionists are devising some kind of season-based diet to help us cope with the vicissitudes of the weather (The Global Warming Cookbook, anyone?). That, in my view, would be taking things too far. None the less, it stands to reason that what you eat should vary at least a bit according to the weather.

But how exactly? From my research, there doesn't seem to be any consensus on the matter. "Try to eat more cold food, particularly salads and fruit, which contain water," the government advises in its "hot weather" guidelines. That is one view - and it makes sense in a way. Cold foods are best in hot weather because they cool you down. But is that actually right? There is another strain of thought which argues the opposite: that you should eat hot foods in hot weather, because this raises your body temperature, making the outside seem relatively cool (or something like that). The cuisines of many hot countries seem to support this: Indians drink endless cups of tea, eat fiery dishes and aren't big on salads; the Thais have their hot soups and also eat plenty of curries. So which is actually better in hot weather? Heat or coldness? And why? Answers on a postcard, please.

What I do believe is unarguable is that spicy foods become more desirable the hotter the weather. These past few weeks I've been craving spice with a rare intensity, ordering extra chilli with my chilli soups and dousing my pizzas in chilli oil. At first I couldn't work out why - and then I realised that it must be the weather. Again, it makes a kind of sense: heat on the inside to override the heat on the outside. And chillies make you sweat, which, in the heat, can only be a good thing.