At this stage in the recovery process, laying horizontal seemed yesterday to be the best option. Resting the Kindle on my stomach, two books seemed perfectly suited to the mellow but guilty mood of the moment – Tim Spector’s “The Diet Myth”, and Rob Knight’s “Follow Your Gut” – all about why diets don’t work, and about those busy little microbes that were toiling away at that very moment helping my body deal with the extraordinary excess of the past two days.

Did you know that our “microbiome” – the mainly-beneficial microbes that populate our bodies in particular in our gut – weighs more than 3 lbs – that is around 1.4 kg, the same weight as our brain. Did you know that compared with the 10 trillion human cells that make up each of our bodies, each of us provide home for 100 trillion microbes, which on average reproduce every 30 minutes.

By my count, that is a heck of a lot of bacteria. But without them, it seems we would be in a big mess – and that imbalances (often linked with using antibiotics every time we catch a cold) can give us problems ranging from irritable bowel syndrome to depression, and of course to diabetes and to obesity.

As concentration lapsed, I inevitably drifted into thoughts about obesity – and how this has soared as poverty continues to plague the unhappy part of the planet. According to the World Health Organisation, in 2014 more than 1.9 billion adults worldwide were overweight, and 600 million were obese – compared with 1 billion struggling below the poverty line and going to bed every day hungry. Alarmingly, a further 43 million kids under 5 years old are obese. And Hong Kong is up there among the fattest. Our Centre for Health Protection says 860,000 Hong Kong adults are obese – about 21 per cent of all adults. That is not as bad as the UK, where over 30 per cent are obese, but not good, and an important source of illnesses like high blood pressure and diabetes.

Hong Kong has a shocking 568,000 people diagnosed with diabetes at present, making it one of the commonest killers in the city, and one of the heavier burdens on our health budget.

Thoughts then drifted to the bigger food issues that we are wrestling with in the 21-member Asia Pacific Cooperation Group (APEC) - food safety, food security, and food waste in particular.

The Peruvian government, chairing APEC in 2016, is giving top priority to food trade and food security. In these discussions, our own government has appeared supine and indifferent for several years – perhaps not surprising since we have no big farm sector, and no apparent food shortages.

Surely this is terribly myopic? Hong Kong has to be among the world’s most food insecure economies, relying on imports for over 90 per cent of our food. If international supplies of food were in any way disrupted (for example, by a major pandemic), then we would have food shortages of epic proportions very quickly.

And despite our massive obesity problems, and widespread overindulgence during festive seasons like this, food security really cannot be taken for granted. Look at some of the numbers that make Malthusians like me lose sleep at night: by 2050, the world’s population is expected to reach 9.1 billion – up 34 per cent from today; The lucky half of that population is expected to be much more affluent, consuming more “resource-wasteful” foods like steak, putting strong upward pressure on demand for cereals; compared to today, where 49% of the region’s population lives in cities, by 2050 we expect 50% of the population to be urban – and as a result unable to grow their own food.

The Food and Agriculture Organisation (FAO) says that cereal production that at present stands at 2.1 billion tonnes a year will have to rise to 3 billion tonnes, while meat production will have to more than double from 200 million tonnes a year to 470 million tonnes.

All of which means that food production must be lifted by 70 to 100 per cent. Given that new farm land is in short supply, this means that just 10 per cent of this new demand can be met by turning new land over to farm land. Some 20 per cent will have to come from improved technologies to use existing cropland more efficiently (note that China, which produces half of the world’s fruit and vegetables, loses half of these fruit and vegetables on the way to market as they rot – that is a quarter of the world’s fruit and vegetables lost every year without us even knowing about it).

A whopping 70 per cent of new food supply must come from new technologies and policy innovation.

So as I laid there with bloated stomach, I realised that my overindulgence cannot in any way be taken for granted in the longer term. You don’t have to be a Malthusian to recognise that food insecurity is a problem we all need to take seriously - to feed those that are still starving, to satisfy the indulgences of the already affluent, and to do so without polluting our planet into extinction. Food for thought.

David Dodwell is executive director of the Hong Kong-Apec Trading Policy Group