Why the story of Leptin is important.
When it comes to hormones, Leptin is the new kid on the block. Discovered in 1994 by Dr Jeffrey Friedman, whilst studying genetic mutations in obese ‘OB’ mice, they were found to have a missing link. The link was a compound that Friedman named Leptin - which is Latin for Thin (1) Its discovery was revolutionary and created a huge amount of excitement - could this be the answer to the world's crisis on obesity? A hormone that controlled the level of weight we could gain by telling us not to over eat - Was this genetic coding the key?
Based on the fact that obesity rates have pretty much doubled since 1994, probably not - but it has become one of the most fascinating hormones that has prompted a huge wealth of research.
Around that time, 1998 in fact, I was involved in a campaign with the BBC entitled ‘Fighting Fat Fighting Fit’(2) Yes, I know! What can I say? It was the nineties! It was though a well intentioned and well placed campaign for that time - there is even a scholarly study on it if you want to take a look! It was successful in that it did get into the homes of so many more people than campaigns previously, but it didn't convert many people to act.
What scares me is that I still hear the same rhetoric from that 90’s title being spouted now. From calorie counting apps to ridiculous ‘fat busting’ myths, or maybe even from your not so well informed doctor, we still hear the words “You just need to eat less and exercise more!” .
Many people I work with are fearful of eating foods containing fat and most diet products and weight loss programmes are still based on a low fat, calorie counting model. All this despite what we now have learnt about just how finely tuned we are. Telling someone to eat less and exercise more is like saying - “See that mountain over there - It’s called Everest - just go climb that! Oh and by the way, your route is 10 times harder than the next persons but don't worry about that!"
Friedman's research and thousands of studies since, tell us there's a completely different story going on inside our body and crucially, our brain which makes the calorie counting model outdated, particularly in the long term. In fact constantly counting calories ultimately leads to greater weight gain...
After Friedman's discovery It was found that giving Leptin to humans who had the same ‘OB’ genetic mutation as the mice, did indeed cause them to lose weight. But the number of people with this specific gene factor were few and far between.(3) (4)
Whilst genealogy sparked a wealth of research, a bigger story on Leptin was emerging - one of how Leptin showed a similar pattern to how our bodies respond to another hormone - Insulin...
In the same way we can become resistant to Insulin,
we can become resistant to Leptin.
Scientists have discovered a number of fascinating facts about Leptin - It has multiple functions which include involvement in our immune system, fertility, bone formation, tissue remodelling and inflammation(10). Regulation of our metabolism is still however its greatest known influence, using signalling pathways, direct to the brain where receptors in the Hypothalamus tell us when we are full and no longer need to eat.
But when this feedback loop doesn’t work, it doesn’t work. It's not necessarily
something you can control, it doesn’t mean you are lazy or useless or
incapable, in fact it’s quite the opposite.
So how do we produce Leptin and what causes us to become resistant to it?
Leptin is produced in Adipose tissue - your fat cells. The more adipose tissue you have, the more Leptin you produce. This is our body's natural response to overfeeding. As we gain weight, Leptin increases so that we feel fuller, and get that signal to eat less. Conversely when we lose weight, Leptin decreases, signalling the brain to tell us to eat more. Many studies report on how this makes dieting and weight loss programmes unsuccessful in the longer term. There’s research to show how many people can lose a lot of weight, gain it, lose it again but over all, they often come back to around or slightly above the same weight at the beginning - this is our in-built homeostasis - it's what our bodies do - and it's pretty cool. However it's no wonder the Diet Industry has survived and thrived for so long...
The Diet Industries success is based on a ‘dieters’ failure
With this constant state of flux, a breakdown occurs in that feedback loop to the brain that stops us from overeating - Yo Yo dieting impacts on our sensitivity to Leptin over time(5). We also know that Leptin plays a key role in modulating Insulin and glucose response, so as we become less sensitive to Leptin, we become less sensitive to Insulin too - hence the link to diabetes and why more research is needed on the role leptin plays within the control of type 2 diabetes(6).
There are also other factors at play…..
Inflammation within the nerve cells generates proteins that dampen our response to Leptin. There is also lot of research on gut health and how certain bacteria are able to permeate through the gut, blocking pathways that signal leptin to activate which leads to an increase in our visceral fat - thats the real damaging fat around our middle.
This all has a lot to do with the quality of our diet. We know that processed foods increase inflammation in tissues and in this instance through neural pathways. In one study, where diet was controlled to mainly refined processed foods, there was an inflammatory response triggered by proteins that are released through gut bacteria. When fermentable fibre was introduced into the diet however, these inflammatory markers were reduced.(7) All this has nothing to do with counting calories and everything to do with the quality of the food we consume.
Leptin is of course just one part of the story that makes up our physiological and psychological make up on metabolism and, as a consequence, visceral fat gain and associated health risks. But because of Leptin's discovery in 1994 it has put us on a new trajectory - one which takes away the blame.
It also puts a warning stamp on the Gut Busters, the Fat Fighters, the Belly Blasters, the Do or Die Dieters and the Go Hard or Go Home diet and exercise regimes. It has pathed the way for a new way of thinking that looks at the psychological as well as the physical.
It has shown us, very clearly, that our obsession with obesity
and our methods for trying to cure it, or shame and blame it, are all wrong.
Leptin has also put genealogy on the obesity map and this is what I find even more interesting. Environment affects our genetic coding. From the history of our agricultural landscape to wars, feast and famine, what happened in the past, impacts on how we respond to weight gain and fat mass now...
Science is showing that history is coded into our genealogy and as a result will impact on our metabolic pathways not just now but for future generations too.(8)
And last but not least, a word on exercise - had to get it in there! Research on the effects of exercise on leptin show favourable results, particularly on lower, sub maximal intensity exercise. This is a huge argument for encouraging everyday movement. Get out there and move, anyway, every day - it does so much more than just burn away a few calories. (9)
There are mixed results on higher intensity exercise in regards to Leptin - it all needs more research and it could be that Cortisol is coming into play here which will feature more in higher intensity exercise. Then of course I could bang on forever about all the other positive affects exercise has on our metabolism.
Worth mentioning Cortisol here, again that's another article, but suffice to say, if your stress levels are high, cortisol, the stress hormone, will rise and there is plenty of evidence to show that this is going to impact on your metabolic pathways and increase visceral fat. And if I had time to go into this, along with sleep, you’ll get the picture as to why all this stuff counts and why counting calories becomes even less significant.
Old habits die hard, never more so than within governments, food industries and the marketers who promote and play on our wants and desires. But knowledge is power and the tide is turning!
And, if by reading this, it encourages you to take a few turns too, then I've done my job!
In all of this - it's your story that matters, and yes it's about a healthy lifestyle - but yours, not anyone else's and here are the simple steps you can take which really aren't too painful if you work on them, bit by bit, one step at a time, your way....
Reducing inflammation by cutting right back on processed foods, eating more fibre and learning about gut health.
Exercising more everyday. Not for amazing abs or a butt to die for - although you can do that too! But most of all, do it for the hell of it and the enjoyment it brings.
Ignoring social media and marketed diet and exercise regimes that are not designed for you - Design your own plan, because you know YOU.
Getting the support of people who know their stuff to help you design your plan - Why not come and join me on my Steptember Campaign?!
Taking small steps with achievable goals that are enjoyable and give you something back.
Getting as much sleep as you can and never ignoring the signs of stress - take a break when you KNOW you need it.
Putting yourself first, because without YOU , nothing else matters.
And the more we support each other to change the way we do this, the more it will impact not just on our own lives but on the lives of those coming up behind us. Not to put the world on your shoulders....But! It's time to be proud of who you are and what you do, not only for your self, but for your future generations too! One step at a time though!
My New campaign - 'Steptember', starts on the 6th September and is a 28 day reset programme, designed to help you take some positive steps forward with the right support and experts around you. To find out more head here
Hope to see you in class soon
1. Zhang Y., Proenca R., Maffei M., Barone M., Leopold L., Friedman J.M. Positional cloning of the mouse obese gene and its human homologue. Nature. 1994;372:425–432. doi: 10.1038/372425a0.
2. Mass education for obesity prevention: The penetration of the BBC's 'Fighting Fat, Fighting Fit' campaign. 2001. Anna Miles et al. Birbeck University.
3. Louis A. Tartaglia et al. Identification and expression cloning of a leptin receptor, OB-
4. Farooqi I.S., Jebb S.A., Langmack G., Lawrence E., Cheetham C.H., Prentice A.M., Hughes I.A., McCamish M.A., O’Rahilly S. Effects of recombinant leptin therapy in a child with congenital leptin deficiency. N. Engl. J. Med. 1999;341:879–884. doi: 10.1056/NEJM199909163411204.
5. 1015.Published online 2019 Dec 11. Physiological and Epigenetic Features of Yoyo Dieting and Weight Control. Raian E. Contreras,et al
7. Patrice D. Cani et al.
Metabolic Endotoxemia Initiates Obesity and Insulin Resistance. Diabetes 2007 Jul; 56(7): 1761-1772.
9. Exercise Improves Insulin and Leptin Sensitivity in Hypothalamus of Wistar Rats. Marcelo B.S et al. Diabetes 2006 Sep; 55(9): 2554-2561.