Why diets fail; it's not what you think. | Krzysztof Czaja | TEDxPeachtree

welcome we go on a diet count every calorie we eat and try to stay within the recommended caloric limit we lose a few pounds and after some time our weight is back again isn't this a story of your life yeah two out of three Americans are either overweight or obese and obesity is a leading driver of many preventable diseases and health care costs currently in the United States estimates go to nearly 250 billion dollars per year and individual costs of obesity are also significant according to colors in calories out theory obesity is a simple matter of eating too many calories what's wrong with it when looking to lose body weight many people cut on fat because it's the most caloric component of our diet even though it's true that weight gain is caused by caloric excess and weight loss is caused by caloric deficit this is still such a drastic oversimplification the fact is that different foods have different effect on our body and go through different metabolic pathways before turning into energy the real problem is focusing on caloric content of foods we eat and disregarding their metabolic effect therefore we shouldn't automatically assume that food with low fat is better for you or will help you lose weight many low fat and fat-free foods can give you more than you bargained for why when fat is removed more sugar is added to make the food taste better and we enjoy our morning fat-free yogurt but when we do a little calculation we can see that only one serving of fat-free yogurt delivers more than 50% of daily recommended amount of added sugar at the beginning of our day we are already more than halfway through our daily limit for added sugar with just one cup of fat-free yogurt and this is just one example of fat-free foods seducing us during the day it is recommended to limit added sugar to 6 teaspoons for a woman and 9 teaspoons for a man per day but average American consumes 23 teaspoons per day and the recommended amount of added sugar is not even labeled in nutrition facts as a result we eat too much sugar three times too much my research team at the University of Georgia in Athens is focusing on a neural gut brain communication using rot as an animal model why rat because both rotten human have similar neural connections between the gut and the brain we are specifically interested in a vagus nerve because the vagus nerve is a two-way street between the gut and the brain signals running from the guard up the vagus nerve to the brain affect our perception of hunger and fullness signals running from the brain down the vagus to the gut affect digestion secretion of digestive enzymes and bowel movement therefore any interruption in avigal godwyn communication may lead to obesity recently God bacteria has added long overlooked component to the complex bi-directional signaling between the gut and the brain triggering a tremendous interest in the field of obesity research changes in a diet composition can rapidly trigger changes in a gut bacteria composition interestingly if we take god bacteria from obese animals and Transplant to germ-free animals with no doubt bacteria they become obese when we take out bacteria from lean animals and Transplant to germ-free animals they become lean this identifies gut bacteria as a potential driver of diet induced obesity in our recent project we investigated the effect of high-fat high-sugar and low fat high sugar diets on gut bacteria gut brain vagal communication and body fat accumulation our high-fat high-sugar diet imitates standard American or western diet while low fat high sugar diet mimics commonly consumed low fat products our results revealed that control rats consuming low fat low sugar diet didn't gain significant amount of body fat over four weeks of the study as we expected rats consuming high fat high sugar diets gain significantly more body fat but surprisingly brats consuming low fat high sugar diet gains significantly more about different than control rats while consuming fewer color additionally we found that rats consuming high sugar diet needed significantly fewer calories to generate the same amount of body fat therefore you can see that color is in calories out theory is not working properly focusing on the quantity and disregarding the quality of food we eat may be the main reason for obesity epidemic next we found that consumption of high sugar diets increase the population of entero toxic bacteria elevating levels of enterotoxin LPS and pro-inflammatory molecules our results revealed that this triggered gut inflammation increased gut permeability and fat accumulation in the liver all these diet induced changes may compromise gut function and lead to obesity in the last step of our study we found that rats consuming high sugar diets develop inflammation in the vagus nerve and brain centers responsible for food intake this altered vagal gut brain communication and was leading to increase body fat accumulation and eventual obesity so long story short we conclude that consumption of high sugar diets is increasing the population of pro-inflammatory bacteria in the gut gastrointestinal inflammation is triggering a cascade of events leading to inflammatory risk in avigal gut-brain communication and brain centers responsible for food intake and this is reflected by increased body fat accumulation and eventual obesity as you can see obvious are overweight people can just eat less and expect automatically to lose body fat eating too much sugar may be toxic to our body but many sugar defenders say that since year 2000 the sugar consumption is going down but obesity rates are still going up and they present the graph where these two trends are going in opposite directions as you can see it's visual a convincing graph it let me wonder about the relevance of our results to obesity but many years ago I learned that if you want the truth then go to this source and I did I checked and in fact according to USDA data the total amount of added sugar consumption is declining since year 2000 but situation of obesity is looking slightly different according to National Center for Health Statistics the observed change in adult obesity between year 2011 and 14 was not statistically different additionally the obesity rate in children didn't change since 2003 so you can see that obesity rates are slowing down since year 2000 as specially in children the population born after year 2000 and why is so important to look at the youth population because they were by average exposed to lower doses of added sugar in their diet and going back to findings from our laboratory they probably experience less damage to their liver less severe inflammation and their damage to vagal gut brain communication was not significant and strong enough to completely destroy neural mechanism of regulating energy intake and expenditure let's look at the numbers this 80% reduction slowed down the obesity rate by an impressive 30% in adults and 45% in children so why is so difficult to lose body fat and stay lean because our neural mechanism regulating energy intake and expenditure is damaged by eating too much sugar while sugar is necessary for healthy life and the consumption trend is going in the right direction we still consume more than 300 percent of daily recommended amount of added sugar instead of counting every calorie you eat count every gram of added sugar because according to the all toxicology Maxim the dose makes the poison thank you very much [Applause] [Music]

Channel: TEDx Talks

Views: 76,804

Rating: 4.8472328 out of 5

Keywords: TEDxTalks, English, Science (hard), Bacteria, Biology, Brain, Disease, Neurology, Neuroscience, Obesity, Research

Id: TSt8A4Iarts

Length: 13min 14sec (794 seconds)

Published: Mon Nov 06 2017