Losing Weight - Why is it so Difficult ? | Andrew Hogan | TEDxUCD

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so we are in the midst of an epidemic an epidemic which represents the greatest challenge to our health and our wealth that we've ever

faced I'm talking about obesity obesity is a worldwide crisis and it affects men women and our

children and even our pets are getting fat so in Ireland one of four adults are currently obese and only two out of 10

of us are registering a healthy body weight so not only are we seeing obesity rates increasing but the levels of obesity that we're seeing are

exploding we've seen a 1200% increase in bmis over 50 a 1200% increase in what we

term super obesity and this all starts in childhood one in five Irish children are now either overweight or

obese and research has shown that obese children have an 82% children chance of becoming obese adults an 82% chance of

lifelong complications and it's not just that they become obese they become super obese and it's because of this that there's no predictions that the life

expectancy for our children is less than their parents so this is unprecedented we've never had a generation of children who have a lower life expectancy than their parents

and it's because with obesity comes a whole range of diseases so obesity has been linked to and causes

diabetes heart disease dementia depression and up to 50% of all cancers can now be directly linked to obesity so because of this obesity is

now killing 3,000 people in Ireland every year and that's the equivalent of 52 double decker buses full of people dying from obesity and its

complications so can you imagine if once a week there was a bus crash and everybody on board was to die we would have immediate

action we would have new laws and new regulations and yet the Irish government have failed to tackle the OB epidemic they failed to implement expert

policy plans for obesity twice and it's because of this failure to tackle the epidemic that the World Health Organization are now predicting that

Ireland will become the most obese Nation among the 52 oecd countries by

2030 So within 14 years we'll be the number one obese country in Europe number one in the Obesity stakes and at

this Stage Nine out of 10 of us will be there overweight or obese so only one in 10 Irish adults will be reging a healthy body weight but

this epidemic will affect us all because today it's costing us three billion euros a year and that represents a quarter of

our total health care budget going on a preventable disease and this is fully preventable and this figure is set to

sore so the question is what's driving this epidemic we look at tree major factors our genetics our activity levels and our

food consumption so our genetics haven't dramatically changed in the last 30 years but yet as we've seen obesity rates are increasing and the levels of obesity we seeing are

exploding so maybe we are more genetically susceptible to modern living but this epidemic is environment driven our activity levels have changed

dramatically we're doing l less than ever before in both our work and our play we're burning less calories than previous

generations we've become a society that's dependent on technology and Hyper convenience and a nice example of this hyper convenience is researchers in the

United States have investigated how many calories we burn when we use a drive-thru and it turns out it's nine we burn nine calories getting our fast food and actually the majority of these

calories come from taking your wallet or your purse out to pay the bill and in an indictment of kind of this modern hyper convenience Society we

live in fast food chains are now letting customers pay for their fast food using their toll pass so you don't have to burn the calories getting your wallet out to pay the

bill and this is for your fast food so we're consuming more calories than ever before and we're burning less calories and we are consuming more calories we now know that were're burning about an

extra 400 calories per day and this represents a 20 to 25% increase in daily intake compared to 40

years ago so we're burning less calories and we're consuming more calories but not only that the type of calorie we're consuming is dramatically different than say our grandparents generation it's

highly processed and it's full of additives and actually these additives are completely changing our Behavior towards food so imagine

this we get SFI or the health research board to buy us some cocaine and then we put that cocaine in the water and we teach a a rat to press

a lever and now it gets some cocaine so that rat becomes addicted to cocaine it's it's an addictive drug then after four days we introduce a second lever and this time there's sugar in the water

so the rat now has a choice lever c will give it some cocaine lever s will give it sugar and what researchers found was over the next 10 days the rats will actually stop

consuming sugar oh cocaine and increase the consumption of sugar they become addicted to sugar and that's because sugar and cocaine act on the same part of the

brain but sugar does it more intensity so it's the same Reward Center but a more intense signal and it's because of this we're consuming more calories so we need more

stimulus this is a reward center of dimin ing returns which means that we need more the stimulus to get the same reward so we're burning less calories

than never before and we're consuming more calories than ever before and the type of calorie we're consuming is making us consume more

calories so what's the solution well our current understanding around obesity is calories in versus calories out if we burn more

calories than we cons assume we'll lose weight and while in theory this is correct meta analysis shows us that this doesn't work it tells us that weight is

90% irreversible for 90% of the population so only one in 10 of us have the ability to lose more than 10% of our body

weight so then the big question is why can't we lose weight so I'm an immunologist and I studi the body's immune system and the

immune system is the body's natural defense against viruses and bacteria and even cancer but what if what if the body is

protecting us against weight loss historically the greatest challenge to us probably wasn't infection or cancer but it was starvation so what if the body and its

immune system has developed a mechanism that stops US burning too much energy to keep them for a rainy

day so my research focuses on the impact of obesity on the immune system and in children as young as five we've seen that obesity chronically

activates the immune system and actually exhausts it to the point where they lose key parts of their immune system so in 2012 we undertook a collaboration with

Harvard University to ask what's the impact of losing part of your immune system so we took a mouse and actually removed part of its immune system a key

cell called a natural killer te- cell but we could have removed any cell and what we expected to see was that maybe that Mouse might get more

infections more autoimmune disease or more cancer like we see in our patients but actually what we found was this the mouse that's missing part of

immune system system became obese and diabetic so this suggests was that the immune system does play a role in body weight so our collaborator

Professor Lydia Lynch asked the question what happens if we put back the immune system into this obese diabetic Mouse and she did just that she injected back

in the missing immune cells and what she found was the mouse lost weight and diabetes went away so again suggest was that the immune system d

play a role in our body weight and not only that but we can actually use this maybe as a therapy for obesity So currently the best therapy we

have for VC is a drug called glp1 and this is an injectable horal and in our patients we might see 20% weight loss so it's not the perfect drug but

it's better than 10% so we ask the question is the immune system involved in weight loss so again we took our mice one with a full immune

system and one missing this key part the inkt cell what we did was we put them on a high fat diet they eat all the bad stuff for 12 weeks and they become obese

and diabetic and get fatty liver disease and then we give our weight loss drug glp1 and in the mouthe that has the full immune system what we seen was weight loss and Improvement in diabetes but

this is a weight loss drug so that's expected but in our mouths missing part of its immune system what we found was a 30% reduction in the amount of weight

lost with a weight loss strug so again this tells us that the immune system is required for weight loss and of course when we look in our patients from the children as young as five all the way

through to our biggest adults they're missing key parts of their immune system this might explain why the energy in energy out equation isn't working for

our patients because the system in the middle is broken so what we got to do now is see can we harness the power of the immune system to tackle obesity so that's the

good news but unfortunately there's no happy ending to this story in our clinics at the moment we're seeing children who at four years of age weigh

Seven Stone and by the time they are 12 years of age they'll weigh 17 Stone and by the time they're young adults 16 17

years of of age they'll weigh 25s St and while these are extreme cases they're far from isolated so we have to tackle this obesity

epidemic we have to educate our children our parents and society as a whole that obesity has to be prevented because as we've seen it's practically

irreversible and if we don't tackle the Obesity epidemic some of our next generation of children are going to end up on one of these buses

thank you [Applause]