I’ve seen headlines about the obesity epidemic recently (e.g. http://www.dailymail.co.uk/health/article-301419/Fat-Britain-Tackling-obesity-epidemic.html).
I’m surprised by the incredulity people show that so many are obese.
Why do you think we evolved to have the taste buds we do, to taste sweet, sour, bitter, salt and umami (the protein taste)?
Sour and bitter are useful guides to food with potential toxins. Salt is needed to balance our body systems, especially the potassium/sodium mix. There’s lots of potassium in vegetables so the hunter/gatherer diet had much potassium and little sodium and we lose salt through sweat, so evolving to the ability to taste it and know what foods to eat to replenish it is beneficial.
Chance mutations meant that people who could taste those things had an advantage over those who couldn’t, and eventually just about everybody could taste them. But consider sweet and umami.
Hunting and gathering is hard, it uses lots of energy – if you’re not expending energy hunting, you’re digging things up, cleaning them, preparing them. And a lot of the time (watch Ray Mears) you seem to expend more energy in getting the food than you can get from the low carbohydrate content in woody roots, or low protein in stringy rodents. So detecting something that had a high calorie content was great, if you could find sugar cane it was pretty well free energy. Same with umami, if you could taste that, you knew you’d got protein.
Think about the selection pressure. If you have genes that allow you to detect and like sweet, what happens? When you find it you eat more of it. Sweet means sugar which means energy, you get more of the easily obtained energy. People with genes that mean they find sweet food nauseating, or that they can take it or leave it, might be able to taste it, but they won’t have any great motivation to eat more of it. People who like sweet food (or umami) will tend to eat more of it. They get more energy (and more protein). They will be more successful in having more offspring, to whom they pass the genes that means a person both detects and likes sweet (and umami). Those genes eventually dominate in the population by sheer numbers, so most of us like the tastes of sweet foods and protein.
So why are we surprised that so many people eat so much sugary food and so many fatty, salty snacks?
Sugary/fatty food is easily available now, we don’t use calories digging it up, hunting it, preparing it. We buy it and eat it. Because of the way we evolved, it tastes nice. We eat more – to the point where we eat far more calories and protein than we actually need, and because our lives are different we have far less need for it than we evolved to use.
And what are the major killers today, that use up millions in NHS budgets for treatment (and even some money in attempts at prevention!)? Heart disease, stroke, cancer, many of which have nutritional links, with incidence of diseases like type 2 diabetes that have very obvious dietary links increasing rapidly.
What to do?
We can tell people not to eat so much, or give them information about the dangers – and that will work as well as health warnings on cigarette packets.
There isn’t a simple answer, but one thing we could do is spend some money on teaching people (particularly children) to cook.
Ready meals are seen as “convenient”, as quick (apparently three quarters of adults see them as “good when you are pressed for time).
Never mind Jamie getting school meals healthier – teaching the parents and children to cook from scratch would be better.
Ready meals are full of sugar and salt (they are preservatives as well as flavouring). They are designed to be tasty, so they have lots of fat, and they don’t have fresh vegetables in (reheat vegetables in a ready meal and you’ll kill a lot of the vitamin content that remained after processing).
There are plenty of meals that can be cooked from scratch in pretty much the same time as a ready meal can be removed from the packaging (that you pay for) and the advantage is that you can use vegetables in season, which have more vitamin content, and are (literally) cheaper than chips. You’re not paying for out of season growth, flying it from around the world and all the packaging and chemicals.
We’re a nation in economic crisis, with an obesity epidemic and unemployment growing.
Why are we spending money we don’t have on food that isn’t healthy, to try to save time that we do have that we probably won’t save anyway?