爲什麼演講稿範文3篇

簡介：在美國，80%的女孩在她們10歲的時候便開始節食。神經學家sandra aamodt結合自己的親身經歷，講述大腦是如何控制我們的身體的。節食減肥爲何沒效果?來聽聽她的說法吧!

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.

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.

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.

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.

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.

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.

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)

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.

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.

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.

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.

thanks.

(applause)

i have the answer to a question that we've all asked. the question is, why is it that the letter x represents the unknown? now i know we learned that in math class, but now it's everywhere in the culture -- the x prize, the x-files, project x, tedx. where'd that come from?

about six years ago i decided that i would learn arabic, which turns out to be a supremely logical language. to write a word or a phrase or a sentence in arabic is like crafting an equation, because every part is extremely precise and carries a lot of information. that's one of the reasons so much of what we've come to think of as western science and mathematics and engineering was really worked out in the first few centuries of the common era by the persians and the arabs and the turks.

this includes the little system in arabic called al-jebra. and al-jebr roughly translates to "the system for reconciling disparate parts." al-jebr finally came into english as algebra. one example among many.

the arabic texts containing this mathematical wisdom finally made their way to europe -- which is to say spain -- in the 11th and 12th centuries. and when they arrived there was tremendous interest in translating this wisdom into a european language.

but there were problems. one problem is there are some sounds in arabic that just don't make it through a european voice box without lots of practice. trust me on that one. also, those very sounds tend not to be represented by the characters that are available in european languages.

here's one of the culprits. this is the letter sheen, and it makes the sound we think of as sh -- "sh." it's also the very first letter of the word shalan, which means "something" just like the the english word "something" -- some undefined, unknown thing.

now in arabic, we can make this definite by adding the definite article "al." so this is al-shalan -- the unknown thing. and this is a word that appears throughout early mathematics, such as this 10th century derivation of proofs.

the problem for the medieval spanish scholars who were tasked with translating this material is that the letter sheen and the word shalan can't be rendered into spanish because spanish doesn't have that sh, that "sh" sound. so by convention, they created a rule in which they borrowed the ck sound, "ck" sound, from the classical greek in the form of the letter kai.

later when this material was translated into a common european language, which is to say latin, they simply replaced the greek kai with the latin x. and once that happened, once this material was in latin, it formed the basis for mathematics textbooks for almost 600 years.

but now we have the answer to our question. why is it that x is the unknown? x is the unknown because you can't say "sh" in spanish. (laughter) and i thought that was worth sharing.

(applause)

尊敬的各位老師，同學們，大家好！

我是法學院大四學生李明，我演講的題目是《我爲什麼要學法律》

很多人聽到這個題目，一定以爲我太把這次演講比賽當做兒戲了。一個簡單的專業選擇的問題，與我們今天的主題“中國夢”能有多大的關聯呢？其實在初入燕園之時，我也只曾在大衆媒體和長輩的口耳相傳中聽得法律職業者的種種評價，也只曾知道“憲法是我國根本大法”之類的政治課本知識，也只曾在路過國徽高懸的莊嚴肅穆的法院門口時好奇的回望。而今，我即將從北大法學院畢業，成爲一名光榮的北大法律人，我所應當肩負的責任是什麼，我可能實現的人生價值在歷史的座標下又是什麼？

我想，這個簡單的問題，不僅僅是我四年燕園求學中努力求索的精神真諦，而且將是指導我未來發展的永恆旗幟。法律人，應該有着怎樣的中國夢，這需要我們用整個人生去回答。

法律人的中國夢，是維護公民合法利益的權利之夢。法治，絕不應當僅僅是宏大的制度構建，而也應當構築起公民權利的堡壘，讓苦幹多年農民工兄弟早日拿到血汗錢，讓徵地拆遷中的血案不再上演，讓猖獗一時的刑訊逼供無處藏身。法學家耶林告訴我們，要“爲權利而鬥爭”，因爲當每個人都在強權面前退卻的時候，整個共同體的利益將不得不被放棄。法律人站在公民權利與強權暴力交鋒的戰場，捍衛每個人的權利，捍衛每個人的中國夢。

法律人的中國夢，是追求社會公平的正義之夢。堅韌的法律人，讓蒼南縣政府做到了被告席上，與浙江普通農民包鄭照對簿公堂。執着的法律人，讓佘祥林、趙作海獲得了他們應得的國家賠償，使冤案昭雪，真相大白。讓比太陽還要光輝的公平正義灑滿人間，是法律人永恆的信條。

法律人的中國夢，是讓中華民族真正實現民主與文明的復興之夢。法律人夢想着讓每個人都有行使民主權利的機會，共享國家發展帶來的成果；法律人希望能夠用制度構建約束權力的牢籠，讓腐木與蛀蟲無處藏身；法律人希望能夠走出一條具有中國特色的民主、法治之路，讓中華民族以更加文明的姿態屹立於世界東方，讓中國夢成爲世界所景仰的精神價值。

也許還有人僅僅是爲了在訴訟和爭議中獲得利益，利用法律規避責任而無視事實真相的存在；也許還有人僅僅是爲了粉飾太平，偏袒強者欺壓弱者，息事寧人而將公平正義束之高閣；也許還有人僅僅是爲了維護舊秩序的穩定，坐擁惡法，助紂爲虐。但中國夢的號角已經吹響，駛向中華民族偉大復興的巨輪已經起航，一切的不完美，都等待着我們去改變。我們怎樣，中國便怎樣。我們是什麼，中國便是什麼。我們有光明，中國便不再黑暗。

在古希臘神話中，代表正義的女神是這樣的形象：她雙眼緊蒙，代表不受干擾和高貴的邏輯理性；她手握天平，代表絕對公平絕不偏袒；她手握利劍，代表踐行正義絕不姑息。法律人，正是懷着崇高的理性精神，踐行對社會公平正義的追求，在推進人類文明的道路上披荊斬棘，爲公民權利而戰，爲公平正義而戰，爲社會進步和民族復興而戰！

我爲什麼要學法律，我想，法律人的中國夢，已經告訴我答案。

我叫馬巖鬆，我是個建築師，我今天講的是，我們爲什麼要談未來，我曾經被一個很重要的批評家問過一個問題，他說，未來將會是什麼，當時我就想怎麼回答這個問題。最後我給他一個答案呢，就是未來就是過去。

大概是XX年吧，這時候我已經在北京工作，我們做了一個競賽，這個競賽在中國的一個大城市，競賽要求建一個四百米的一個樓，然後政府的人說，雖然我們寫的是400米，但是呢，你們可以來表達你們認爲的一個高度，他這個話呢大家都明白了，就是他想要一個更高的，他要一個更高的樓，來表達這個城市的一個信心。結果呢，所有的建築師都設計了一個高於400米的，高於400米，500米，600米，當時還沒有迪拜這個800米的事兒，然後我當時就想，那我就來一個800米的吧。然後我跟政府彙報的第一句就是你想要一個世界第一高的樓嗎?我們這是一個800米的，但是這個800米的樓呢，其實只有400米，但是它是兩截，400米上去了然後又轉下來，一共800米。等於是樓頂又回到了地面，然後我們就輸了，不但輸了，而且十幾年過去了，我們現在還沒拿到設計費，就是他們生氣了。生氣呢，我覺得可能是這個，對這個玩笑有點接受不了，很多地方都想建超越盤，建一個更高的樓，用更高的樓代表他們的野心。可是現在時間又不一樣了，現在我們已經開始上火星了，技術已經很發達，建一個高層建築其實並不難，挑戰不了技術，只是挑戰錢，所以高層建築就慢慢變成了權力和資本的一個紀念碑，所以這個時代呢，我覺得已經不是再去讚美權力和資本的時代了。都想建大樓，都想用高樓來代表他們的信心，來代表一個城市創造力的時候，我就覺得非常愚蠢，所以把這個玩笑當成是一種對現實的批判。每一個對現實的批判，我都認爲指向一個更好的未來。但這個未來呢，就永遠不發生。

每一次我們的提案都是輸，直到我們做了一個競賽，是在國外，我們贏了一個高層建築的競賽，這個項目在加拿大，在北美，大家都直到我們今天中國的城市都是在山寨北美，北美是高層建築，是這種現代城市的故鄉，我們在北美能設計一個房子，我就想能不能去，不去跟其他的樓一樣，去搶這樣的高度，力量，我設計一個自然的高層建築，因爲很多人說這個曲線像一個女人的曲線，然後加拿大管這個樓叫“夢露大廈”，然後我們就有一天收到一封信，就說你們入圍了，這時候我覺得非常地習慣，因爲入圍之前，我們經常入圍，但是我們確定他們不會選我們。第一因爲我們是中國的，中國的建築師，在北美設計一個房子，以前從來沒聽說過。第二，我覺得他們讓我們入圍，可能是看上我們的這個圖，跟他們以前建造的這些高樓，都不一樣。但是當建造的時候，可能所有人都該說，怎麼建呀?結構是什麼樣?會不會花很多錢?但我還是去了，我一點也不緊張。我覺得，我覺得我就是抱着一種不會被選上這麼一個心態去。不會被選上的心態對我來說是非常重要的。如果被選上了，我會覺得心裏不舒服，我會覺得他們看懂我了，我會覺得我可能諂媚他們了，爲什麼我的批判，我的玩笑，我對他們的刺激，還能被他們高興地接受。所以那樣的結果，可能對我來說更殘酷的，我基本上已經習慣了不被接受的，不能建的這個狀態。又過了兩個月，他們最後決定要建我們這個樓了，我覺得他們瘋了，但我又說不出來爲什麼他們瘋了，我只知道大部分人不會做這樣的決定，我也爲他們捏把汗，因爲那時候我還基本上沒怎麼工作過，我也沒建過什麼房子。我想如果你們誰家想蓋一房子，找一建築師，至少這個人以前是蓋過房子的吧，更何況是建一個城市地標。所以這件事突然讓我有了信心，我覺得我好像也能建房子了。

但我又有一點害怕，我覺得我批判，一個指向未來的建築，怎麼說蓋就蓋起來了，這個未來是不是，本來就不是未來啊。所以當這個高層建築在北美開工的時候，我就在想，我真正的未來是什麼?山水城市，我認爲是源於對未來的渴望，是要解決現實的問題，是想建造一個有情感的、有自然的、有生活的這樣的城市。我們現在呢，又是在這麼一個階段，就是生活在自己的臆想裏面，你要問我具體的問題，說這個到底是什麼，我也不知道。但是我喜歡這種狀態，讓我越來越接近未來，我希望能跟未來有一個對話，謝謝!