Sunday, 11 September 2011

Observing Factors Regulating Body Fat

A couple of interesting articles in today's Observer.  The article "A 'lean gene' causes thinness" recognises that regulation of body fat is subject to genetic factors.  Recognition is even given to the impact of food quality on bodyfat levels, although to my mind the analysis ends in an epic fail, clinging as it does to an 'eat less, do more'/'calories in vs calories out' paradigm:

  • In many countries, including the UK, social services are keen to blame parents when children are too heavy or too thin. I think it is important for people who work in social or health services to know that children may be underweight because of genetic factors. It is easy and inexpensive to analyse genetics these days. When you have the answer, you don't take the child to a psychologist, you don't try to increase their appetite; instead you take them to a dietician and try to increase the quality of their food – they won't eat more but if you can increase the density of calories you can increase the weight. We do the same for people who have cancer or old people.
Given the claim that obesity in the west has,erm, 'ballooned' in the past twenty years, we should be looking for what is causing our genes to express themselves in the way they are.  Abundance of food and to some degree, food palatibility don't seem to offer much by way of explanation to me as I don't seem to recall the great western famine of the 1980s, nor do I remember that food tasted bad back then.  Basically I cannot remember a time when food wasn't available in abundance to all of us in the west, and boy, didn't it always taste good?

So on to 'Experts targeting obesity raise hope of drugs to stop us feeling hungry'.  Experts eh?  You've go to love them.  The experts who are targetting obesity in this article are probably economists and accountants, but I digress (when I should be ranting):
  • "Humans evolved at times when food was scarce and when we faced starvation all the time," says Professor Waljit Dhillo, at Imperial College, London. "Those who survived were the ones who were able to eat most food and could sustain themselves through periods of famine. They passed on the genes for that ability to future generations. It was useful then, when times were hard, and it ensured our species survived famines.
You know when I see statements like the one above my anthropological BS detector fires big-time.  Consider us in our true context as animals; now how many wild animals have a robust source of food?  Pretty much all of them.  The only ones who have a fragile source of food are modern humans (post agriculture).  If you don't believe me then you should have seen what happened in the UK supermarkets during the fuel strikes of 2000,
  • During the 2000 fuel strike, Sainsbury’s chief executive wrote to the prime minister to warn that food supplies would run out “in days rather than weeks”. Supermarkets rationed bread, sugar and milk.
Sure there are longer term swings in terms of food availability, and you cannot rule out black-swan events, but you'd imagine we were ALWAYS on the pin-head of famine, and I don't really buy that.  A cursory look at wildlife (and any quality survival program), shows that food is in abundance in most terrains if you know where to look for it.  Humans THRIVED in marginal areas and used migratory tactics to ensure their survival.  There is none so blind as an agriculturist or a consumer.  Or a scientist,
  • "There appears to be many chemicals involved in sending chemical messengers from the gut to the brain," added Dhillo. "The trick is to find the most important ones."

    A region of the brain called the hypothalamus plays a critical role in dealing with digestion and controls chemical messengers that pass between the brain and the gut. Researchers have isolated two of these messengers, chemicals released by cells in the intestine which are closely linked to appetite suppression. One is known as Glucagon-like peptide-1, or GLP-1, and the second is known as Peptide YY, or PYY. "We recently carried out experiments on adults who had fasted for 12 hours," added Dhillo. "We monitored their brain activity and found, when we showed them pictures of food, particular areas of their brains lit up in our scanners. It was a measure of how interested they were in food.


    "Then we gave them an infusion of GLP-1 and PYY and again showed them the pictures of food. Their brains did not light up nearly so much. In other words, they were less stimulated by the sight of food. They had lost their hunger. Essentially, PYY and GLP-1 suppressed their appetites."


    Both hormones break down easily in the gut and so their direct use as a drug is limited. However, chemically altered versions of GLP1 – known as exenatide and liraglutide – are already used as a treatment for diabetes because they cause weight loss and also boost insulin secretion in the body. "The trouble with these drug hormones is that they are short-acting," added Dhillo. "Most break down quickly. So pharmaceutical companies are developing analogue versions which have the same effect but last for longer in the body. Some could be administered once a week.


    "The future will be to develop a multi-hormone injection that is given in a low dose, so that you do not get any side-effects, and will be long-acting enough so that you need only take it once a day or once a week.
Given the decentralised nature of control throughout the body, the complexity of the energy and signalling systems and so forth, I am sure most of us cannot wait for someone to swing a pharmaceutical sledgehammer to crack a small nut; a cure for obesity which short-circuits the hormonal control system governing energy regulation.  I guess it is no better or worse than the hard engineering of gastric banding, cutting out the fat or eating lowfatcrapinabox, but hell, shouldn't we first be looking at WHY we are getting fat?  At WHY obesity is trending the way it has done in the past 20 years?

You always have to ask yourself with these 'cures' whether they are treating a symptom or the underlying cause.  Follow the money and don't expect to 'get well'.

1 comment:

FeelGoodEating said...

Fecking brilliant!!!

Its amazing really!!
Cheers
Marc