Three and a half years ago, I made one of the best decisions of my life. As my New Year's resolution, I gave up dieting, stopped worrying about my weight, and learned to eat mindfully. Now I eat whenever I'm hungry, and I've lost 10 pounds.
Hai tres anos e medio, tomei unha das mellores decisións da miña vida: como propósito para o novo ano, deixei de facer dietas, de preocuparme polo meu peso e aprendín a comer de maneira consciente. Agora como cando teño fame, e perdín 4'5 kg.
This was me at age 13, when I started my first diet. I look at that picture now, and I think, you did not need a diet, you needed a fashion consult. (Laughter) But I thought I needed to lose weight, and when I gained it back, of course I blamed myself. And for the next three decades, I was on and off various diets. No matter what I tried, the weight I'd lost always came back. I'm sure many of you know the feeling.
Esta son eu con 13 anos, cando comecei a miña primeira dieta. Cando vexo esa foto penso: "non precisabas poñerte a réxime, o que precisabas era aprender a vestir". (Risas) Pero eu estaba convencida de que necesitaba perder peso e cando o recuperaba, culpábame a min mesma, madía leva. E durante as tres décadas seguintes, probei e probei distintos réximes. Daba igual o que fixese, despois de perder peso, volvía gañalo. Estou segura de que moitos de vós compartides ese sentimento.
As a neuroscientist, I wondered, why is this so hard? Obviously, how much you weigh depends on how much you eat and how much energy you burn. What most people don't realize is that hunger and energy use are controlled by the brain, mostly without your awareness. Your brain does a lot of its work behind the scenes, and that is a good thing, because your conscious mind -- how do we put this politely? -- it's easily distracted. It's good that you don't have to remember to breathe when you get caught up in a movie. You don't forget how to walk because you're thinking about what to have for dinner.
Como neurocientífica preguntábame "por que é tan difícil?". Obviamente, o noso peso depende do que comemos e da enerxía que queimamos. O que a maioría da xente non sabe é que o cerebro controla a fame e o consumo de enerxía, sobre todo, de maneira inconsciente. O noso cerebro fai este traballo entre bastidores, e iso é unha boa noticia, xa que a nosa mente consciente --como dicir isto de maneira educada?-- distráese con facilidade. Está ben o de non ter que acordarse de respirar mentres estamos a ver unha película. Ou o de non esquecernos de como camiñar mentres pensamos no que imos cear.
Your brain also has its own sense of what you should weigh, no matter what you consciously believe. This is called your set point, but that's a misleading term, because it's actually a range of about 10 or 15 pounds. You can use lifestyle choices to move your weight up and down within that range, but it's much, much harder to stay outside of it. The hypothalamus, the part of the brain that regulates body weight, there are more than a dozen chemical signals in the brain that tell your body to gain weight, more than another dozen that tell your body to lose it, and the system works like a thermostat, responding to signals from the body by adjusting hunger, activity and metabolism, to keep your weight stable as conditions change. That's what a thermostat does, right? It keeps the temperature in your house the same as the weather changes outside. Now you can try to change the temperature in your house by opening a window in the winter, but that's not going to change the setting on the thermostat, which will respond by kicking on the furnace to warm the place back up. Your brain works exactly the same way, responding to weight loss by using powerful tools to push your body back to what it considers normal. If you lose a lot of weight, your brain reacts as if you were starving, and whether you started out fat or thin, your brain's response is exactly the same. We would love to think that your brain could tell whether you need to lose weight or not, but it can't. If you do lose a lot of weight, you become hungry, and your muscles burn less energy. Dr. Rudy Leibel of Columbia University has found that people who have lost 10 percent of their body weight burn 250 to 400 calories less because their metabolism is suppressed. That's a lot of food. This means that a successful dieter must eat this much less forever than someone of the same weight who has always been thin.
O noso cerebro ten o seu propio concepto do que debemos pesar, sen importarlle o que opine o noso ser consciente. A isto chámaselle "punto de partida", pero é un termo enganoso, xa que realmente comprende un rango de entre 4,5 e 7 kg. Podemos cambiar o noso estilo de vida para subir ou baixar de peso dentro dese rango, pero é moitísimo máis difícil manterse fóra del. No hipotálamo, a parte do cerebro que regula a masa corporal, hai máis dunha ducia de sinais químicos que lle indican ao corpo que gañe peso, e máis doutra ducia que lle indican que o perda. Este sistema funciona como un termóstato, responde aos sinais do corpo con axustes nos niveis de fame, na actividade e no metabolismo, co fin de manter o noso peso estable mentres que as condicións cambian. Iso é o que fai un termóstato, non si? Mantén a temperatura da casa mentres que o tempo fóra cambia. Podemos intentar cambiar a temperatura da casa abrindo unha ventá no inverno, pero iso non vai cambiar os axustes do termóstato, co que a súa resposta será avivar a caldeira para que o espazo queza de novo. O noso cerebro funciona do mesmo xeito, responde ao enfraquecemento con ferramentas moi poderosas que o forzan a recuperar o peso que considera normal. Se perdemos moito peso, o cerebro reaccionará como se estivésemos a morrer de fame, e tanto se eramos gordos como fracos, a resposta vai ser idéntica. Encantaríanos que o noso cerebro soubese se precisamos gañar peso ou non, pero non o sabe. Se perdemos moito peso, teremos moita fame, e os nosos músculos queimarán menos enerxía. O Dr. Rudy Leibel da Universidade de Columbia descubriu que as persoas que perderon un 10% do seu peso corporal queimaban entre 250 e 400 calorías menos por teren o seu metabolismo suprimido. Iso é moita comida! E implica que o que siga esa dieta debe comer iso de menos toda a vida en comparación con alguén do mesmo peso que sempre foi delgado.
From an evolutionary perspective, your body's resistance to weight loss makes sense. When food was scarce, our ancestors' survival depended on conserving energy, and regaining the weight when food was available would have protected them against the next shortage. Over the course of human history, starvation has been a much bigger problem than overeating. This may explain a very sad fact: Set points can go up, but they rarely go down. Now, if your mother ever mentioned that life is not fair, this is the kind of thing she was talking about. (Laughter) Successful dieting doesn't lower your set point. Even after you've kept the weight off for as long as seven years, your brain keeps trying to make you gain it back. If that weight loss had been due to a long famine, that would be a sensible response. In our modern world of drive-thru burgers, it's not working out so well for many of us. That difference between our ancestral past and our abundant present is the reason that Dr. Yoni Freedhoff of the University of Ottawa would like to take some of his patients back to a time when food was less available, and it's also the reason that changing the food environment is really going to be the most effective solution to obesity.
Dende unha perspectiva evolutiva, a resistencia do noso corpo a perder peso ten sentido. Cando a comida era escasa, a supervivencia dos nosos antepasados dependía da conservación da enerxía, e mais da recuperación do peso tras a escaseza, xa o que os protexería nas vindeiras penurias. No transcurso da historia da humanidade, a falta de alimento foi un problema máis grave que o abuso no seu consumo. Isto pode explicar un feito moi triste: os "puntos de partida" poden incrementar, pero case nunca decrecen. Se a túa nai algunha vez menciona que a vida non é xusta, esta é a clase de cousas ás que se refire. (Risas) Facer dieta de maneira correcta non vai diminuír o teu "punto de partida". Incluso cando consegues manter teu peso durante 7 anos, o teu cerebro segue loitando para que o volvas recuperar. Esta resposta sería axeitada se a perda de peso se debese a unha longa época de fame. No mundo actual, no que existen hamburguesas para levar, este sistema non funciona tan ben para moitos de nós. Esa diferenza entre o pasado no que viviron os nosos antepasados e o noso presente de abundancia é a razón pola que o Dr. Yoni Freedhoff da Universidade de Ottawa querería levar algún dos seus pacientes a un pasado no que a comida era limitada, e esa tamén é a razón pola que cambiar a dispoñibilidade dos alimentos, é a solución máis efectiva para combater a obesidade. Por desgraza, unha ganancia temporal de peso
Sadly, a temporary weight gain can become permanent. If you stay at a high weight for too long, probably a matter of years for most of us, your brain may decide that that's the new normal.
pode converterse en permanente. Se mantemos un peso elevado durante moito tempo, falo de anos para a maioría de nós, pode que o noso cerebro decida que ese é o peso normal. Os psicólogos clasifican as persoas en dous grupos:
Psychologists classify eaters into two groups, those who rely on their hunger and those who try to control their eating through willpower, like most dieters. Let's call them intuitive eaters and controlled eaters. The interesting thing is that intuitive eaters are less likely to be overweight, and they spend less time thinking about food. Controlled eaters are more vulnerable to overeating in response to advertising, super-sizing, and the all-you-can-eat buffet. And a small indulgence, like eating one scoop of ice cream, is more likely to lead to a food binge in controlled eaters. Children are especially vulnerable to this cycle of dieting and then binging. Several long-term studies have shown that girls who diet in their early teenage years are three times more likely to become overweight five years later, even if they started at a normal weight, and all of these studies found that the same factors that predicted weight gain also predicted the development of eating disorders. The other factor, by the way, those of you who are parents, was being teased by family members about their weight. So don't do that. (Laughter)
os que se fían da súa fame e os que intentan controlar o que comen con forza de vontade, como a maioría dos que seguen dietas. Referireime a eles como "comedores intuitivos" e "controlados". O interesante dos "comedores intuitivos" é que teñen unha menor tendencia ao sobrepeso e pasan menos tempo pensando na comida. Os "comedores controlados" son máis vulnerables a comer de máis motivados pola publicidade, piden as racións máis grandes e sucumben aos bufetes libres. Un pequeno capricho, como comer unha soa cullerada de xeado, fai aos "comedores controlados" máis propensos á farta de comida. Os nenos son moito máis sensibles a este ciclo de facer dieta e logo comer a fartar. Numerosos estudos mostran que as rapazas que fixeron dieta durante o comezo da adolescencia teñen unha probabilidade 3 veces maior de padeceren sobrepeso cinco anos despois, incluso cando partían dun peso normal, e todos estes estudos atoparon que os mesmos factores que predín a ganancia de peso serven para predicir tamén trastornos alimentarios. O outro factor, por certo, para aqueles que sodes pais, son as burlas por parte dos membros da familia sobre o seu peso. Así que non fagades iso. (Risas)
I left almost all my graphs at home, but I couldn't resist throwing in just this one, because I'm a geek, and that's how I roll. (Laughter) This is a study that looked at the risk of death over a 14-year period based on four healthy habits: eating enough fruits and vegetables, exercise three times a week, not smoking, and drinking in moderation. Let's start by looking at the normal weight people in the study. The height of the bars is the risk of death, and those zero, one, two, three, four numbers on the horizontal axis are the number of those healthy habits that a given person had. And as you'd expect, the healthier the lifestyle, the less likely people were to die during the study. Now let's look at what happens in overweight people. The ones that had no healthy habits had a higher risk of death. Adding just one healthy habit pulls overweight people back into the normal range. For obese people with no healthy habits, the risk is very high, seven times higher than the healthiest groups in the study. But a healthy lifestyle helps obese people too. In fact, if you look only at the group with all four healthy habits, you can see that weight makes very little difference. You can take control of your health by taking control of your lifestyle, even If you can't lose weight and keep it off.
Deixei na casa case todas as miñas gráficas, pero non me puiden resistir a traer esta, porque son unha "friki" e iso é o meu. (Risas) Este é un estudo sobre o risco de morte ao longo de 14 anos baseado en catro hábitos saudables: comer suficiente froita e verdura, facer exercicio tres veces á semana, non fumar, e beber con moderación. Comecemos analizando os participantes de peso normal. A altura das barras indica o risco de morte, e os números 0, 1, 2, 3 e 4 no eixo horizontal representan a cantidade destes hábitos que presenta unha persoa dada. Como podedes imaxinar, canto máis san é o estilo de vida, menor é a probabilidade de morte destes individuos durante o estudo. Agora vexamos o que pasa coas persoas con sobrepeso. As que non teñen hábitos saudables teñen un maior risco de morte. Ao cambiar soamente un dos hábitos, as persoas con sobrepeso entrarían no rango normal. Para as persoas obesas sen hábitos saudables, o risco é moi alto, incluso 7 veces maior que o dos grupos máis sans do estudo. Pero un estilo de vida saudable axúdalles tamén ás persoas obesas. De feito, se atendemos soamente ao grupo cos catro hábitos saudables, vemos que o peso ten un efecto moi pequeno. Podemos controlar a nosa saúde controlando o noso estilo de vida, incluso sen sermos capaces de perder peso e mantelo. As dietas son pouco fiables.
Diets don't have very much reliability. Five years after a diet, most people have regained the weight. Forty percent of them have gained even more. If you think about this, the typical outcome of dieting is that you're more likely to gain weight in the long run than to lose it.
Cinco anos despois dunha dieta, a maioría da xente volve recuperar o peso. O 40% deles incluso gañan máis. Se pensades nisto, o resultado habitual dunha dieta é ter maior facilidade para gañar peso que para perdelo.
If I've convinced you that dieting might be a problem, the next question is, what do you do about it? And my answer, in a word, is mindfulness. I'm not saying you need to learn to meditate or take up yoga. I'm talking about mindful eating: learning to understand your body's signals so that you eat when you're hungry and stop when you're full, because a lot of weight gain boils down to eating when you're not hungry. How do you do it? Give yourself permission to eat as much as you want, and then work on figuring out what makes your body feel good. Sit down to regular meals without distractions. Think about how your body feels when you start to eat and when you stop, and let your hunger decide when you should be done. It took about a year for me to learn this, but it's really been worth it. I am so much more relaxed around food than I have ever been in my life. I often don't think about it. I forget we have chocolate in the house. It's like aliens have taken over my brain. It's just completely different. I should say that this approach to eating probably won't make you lose weight unless you often eat when you're not hungry, but doctors don't know of any approach that makes significant weight loss in a lot of people, and that is why a lot of people are now focusing on preventing weight gain instead of promoting weight loss. Let's face it: If diets worked, we'd all be thin already. (Laughter) Why do we keep doing the same thing and expecting different results? Diets may seem harmless, but they actually do a lot of collateral damage. At worst, they ruin lives: Weight obsession leads to eating disorders, especially in young kids. In the U.S., we have 80 percent of 10-year-old girls say they've been on a diet. Our daughters have learned to measure their worth by the wrong scale. Even at its best, dieting is a waste of time and energy. It takes willpower which you could be using to help your kids with their homework or to finish that important work project, and because willpower is limited, any strategy that relies on its consistent application is pretty much guaranteed to eventually fail you when your attention moves on to something else.
Se xa vos convencín de que facer dieta pode ser un problema, a seguinte pregunta é: que se pode facer entón? E a miña resposta, en dúas palabras, é "pensamento consciente". Non estou falando de aprender a meditar ou a facer ioga. Falo de comer de maneira consciente: aprender a interpretar os sinais corporais, e comer só cando temos fame e parar cando estamos cheos, porque moitas veces a ganancia de peso débese a que comemos sen fame. Como podemos facelo? Permítete comer tanto como queiras, e logo trata de recoñecer que fai que o teu corpo se sinta ben. Para as comidas principais senta a comer sen distraccións. Pensa en como se sente o teu corpo cando comezas a comer e cando rematas, e deixa que a túa fame decida cando debes facelo. A min levoume máis ou menos un ano aprender iso pero merece moito a pena. Estou moito máis cómoda en relación coa comida do que o estiven xamais na vida. Polo xeral, non penso nela. Esquézome de que temos chocolate na casa. É como se os extraterrestres se fixesen co meu cerebro. Completamente distinto. Debo dicir que este enfoque non che fará perder peso a non ser que esteas a comer sen fame, pero os médicos non coñecen ningún outro enfoque que faga que moita xente perda peso de maneira significativa, e ese é o motivo polo que actualmente moita xente se centra en previr a ganancia de peso en vez de en promover a súa perda. Sexamos sinceros: se as dietas funcionasen, xa estaríamos todos fracos. (Risas) Por que seguimos facendo o mesmo pero esperamos resultados distintos? As dietas poden parecer inofensivas, pero en realidade, provocan danos colaterais. O peor é que arruínan vidas: a obsesión polo peso conduce a trastornos alimentarios sobre todo nos máis novos. Nos EUA, o 80% das rapazas de 10 anos din que fixeron dieta algunha vez. As nosas fillas aprenderon a medir a súa valía coa escala equivocada. Na mellor das hipóteses, facer dieta é unha perda de tempo e de enerxía. Malgasta unha forza de vontade que poderiamos utilizar en axudar aos nosos fillos coas tarefas ou en acabar ese proxecto tan importante, e como a forza de vontade é limitada, calquera estratexia que a precise é ben seguro que vai fallar en canto a túa atención se desvíe deica outra cousa.
Let me leave you with one last thought. What if we told all those dieting girls that it's okay to eat when they're hungry? What if we taught them to work with their appetite instead of fearing it? I think most of them would be happier and healthier, and as adults, many of them would probably be thinner. I wish someone had told me that back when I was 13.
Déixovos cun último pensamento: que pasaría se lles dixésemos a esas rapazas que fan dieta que está ben comer cando teñen fame? que tal se lles ensinamos a traballar o seu apetito en vez de a terlle medo? Supoño que a maioría delas serían máis felices e máis sas, e como adultas, moitas delas serían máis fracas. Encantaríame que alguén me contase isto canto eu tiña 13 anos.
Thanks.
Grazas.
(Applause)
(Aplausos)