Food is getting ever more convenient. The latest innovation appears to be on-demand grocery companies, which are popping up in cities across the UK. Apparently, getting food, snacks and drinks delivered to your sofa within 10 minutes is the next big thing. The question is, is it a good thing for your health?
According to the Guardian, nearly £10 bn has been invested in on-demand grocery companies since the start of the pandemic. That’s a pretty big bet. And, knowing our unwavering pursuit of convenience and ease, I’d say it’s a pretty good bet.
But it’s likely to be bad news for our waistlines and our health, because it will make it even easier to obtain and overeat calorie dense, ultra-processed food, while being even more sedentary.
As a population we eat badly here in the UK. Less than 30% of our calories come from unprocessed or minimally processed food. And more than 50% come from ultra-processed (junk) food. Our poor eating habits are reflected in our poor health, with nearly two thirds of adults now being overweight or obese.
We are in the midst of an obesity epidemic. And the ubiquitous access to highly processed convenience food is the primary cause.
While the choice at the on-demand groceries is somewhat limited at the moment, I think we can assume that the food and drink ultimately made available will be representative of current availability and demand across the food market (i.e. heavily skewed towards processed food). That would be the economically rationale approach. So, it’s unlikely that on-demand grocery will improve the food choices of the nation. It will just make it easier to eat how we’re already eating.
It’s well-established in behaviour science that the easier a behaviour is to do the more likely we are to do it. For the small proportion of the population who eat healthily, on-demand groceries will make it easier to eat healthily, making healthy diets more sustainable. That’s a good thing. But for the large proportion of the population who eat unhealthily, it will be even easier to eat unhealthily, which is likely to mean a further increase in the consumption of ultra-processed food. That’s a bad thing.
Furthermore, whether on-demand grocery delivery is used for healthy or unhealthy foods, physical activity and time outdoors will be reduced for every user – less walking to and from the local shop, less carrying bags home – unless the time saved is allocated to exercise (which seems unlikely for most people). Physical activity levels are already very low, and this would only make it worse, which is negative for pretty much every aspect of health.
Humans (like other animals) have evolved to obtain the maximum number of calories with the minimum amount of effort in a given environment. We are hard-wired to seek out and overeat the highest calorie most convenient food available, and store excess energy (as fat) for later use. This served us well throughout most of evolution in an environment where food was often hard to come by and always took a lot of effort to obtain. But, in today’s environment of extremely calorie dense convenience foods, it works against us.
The food seeking behaviour of human hunter-gatherers is complex, but it has been accurately modelled by a framework called Optimal Foraging Theory (OFT), and the maths is surprisingly simple:

The more calories a food contains the higher its value. The fewer the calories expended and/or the less time consumed to obtain a food (in other words, the more convenient a food is) the higher its value. Higher value foods are more likely to be to be pursued and, if obtained, overeaten.
As far as eating behaviour goes, we are still hunter-gatherers. On-demand grocery companies are substantially increasing the convenience of food, making calorie dense, ultra-processed junk food even more valuable than it already is. It’s akin to installing a huge vending machine in our living rooms. Imagine what that would do to our eating habits. In fact, you don’t have to imagine, that experiment has been done. When subjects were given unlimited access to a vending machine full of calorie dense convenience food, daily calorie intake increased by more than 50% and body weight increased by 1 kg in 5 days.
The effect on consumption of minimally processed food is different. Unlimited access to ultra-processed foods leads to overeating and rapid weight gain, whereas unlimited access to minimally processed foods leads to a reduction in calorie intake and weight loss. But only a very small segment of the population eats this way – and on-demand grocery is unlikely to change this.
The march of food calorification and convenication in Western countries over the last 50 years has been unstoppable. During that time, the continual increase in overweight and obesity rates has been equally as unrelenting, devastating public health. Do we really want to continue making ultra-processed foods ever more convenient to obtain, to continue making our lives easier, to continue making ourselves sicker? If we’re not careful, we may fulfil the bleak future predicted in the excellent Pixar film Wall-E.
