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Need a determination boost to complete those New Year's Resolutions (or really any kind of resolution)? Look no further than this compilation of SciShow videos from SciShow of yore.

Why Our Brains Love Junk Food - 1:11
3 Terrible Old-Timey Ways to (Not) Lose Weight - 4:44
How Many Calories Should I Have in a Day? - 8:21
When You Burn Fat, Where Does it Go? - 11:11
The Science of Hangovers - 13:38
5 Weird Reasons Not to Smoke - 16:57
Dooblydoo thanks go to the following Patreon supporters -- we couldn't make SciShow without them! Shout out to Justin Ove, Justin Lentz, David Campos, Chris Peters, Philippe von Bergen, Fatima Iqbal, John Murrin, Linnea Boyev, and Kathy & Tim Philip.
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Why Our Brains Love Junk Food
Hank Green - Director / Instructor (Host)
Nick Jenkins - Director of Photography
Jesslyn Shields - Writer
Peter Winkler - Animator
Blake De Pastino - Chief Editor
Matt Ferguson - Editor
Michael Aranda - Sound Designer
Amber Bushnell - Creative Director / Lead Designer
Diet & the evolution of the earliest human ancestors -
Australopithecus: Diet -
Did cooking make us human? -

3 Terrible Old-Timey Ways to (Not) Lose Weight
Hank Green - Executive Producer
Blake De Pastino - Chief Editor
Caitlin Hofmeister - Producer
Michael Aranda - Host
Alyssa Lerner - Writer
Sarah Meismer - Video Editor / Graphics
Stefan Chin - Script Supervisor
Louey Winkler - Camera

How Many Calories Should I Have in a Day?
Hank Green - Executive Producer
Blake De Pastino - Chief Editor / Writer
Michael Aranda - Host
Caitlin Hofmeister - Producer
Stefan Chin - Graphics
Louey Winkler - Camera
Sarah Meismer - Script Supervisor / Editor

When You Burn Fat, Where Does it Go?
Hank Green - Executive Producer
Blake De Pastino - Writer / Chief Editor
Caitlin Hofmeister - Producer / Script Supervisor
Sarah Meismer - Video Editor
Sarah Gullickson - Graphics
Michael Aranda - Host

The Science of Hangovers
Hank Green - Instructor (Host) / Director
Blake De Pastino - Chief Editor
Lou Winkler - Graphics Team
Nick Jenkins - Director of Photography
Caitlin Hofmeister - Video Editor / Camera Operator
Kathleen Yale - Writer
Peter Winkler - Creative Director

5 Weird Reasons Not to Smoke
Hank Green - Director / Instructor (Host) / Writer
Blake De Pastino - Chief Editor
Nick Jenkins - Director of Photography
Matt Ferguson - Editor
Michael Aranda - Sound Designer
Peter Winkler - Animator
Amber Bushnell - Creative Director / Lead Designer
References for this episode can be found in the Google document here:

 Intro (00:00)

[SciShow Intro plays]

Hank: Hello and happy New Year. I know the new year was a while ago, but New Year's resolutions are supposed to last, at least until now, right? You seemed to like our first compilation video so we decided to do it again and this time, we wanted the videos we included to be inspired by all of you, so we decided to focus on your resolutions. We asked our patrons on Patreon what their New Year's resolutions were and you know what we learned? Or really had confirmed: you people are cool. Some of you are finishing PhD's, learning new things like how to scuba dive or dance, some of you are getting dogs, some of you are devotedly getting stuck by not having resolutions for 20-some years, so good job on completing that resolution? And while you're sticking to it and improving yourselves, enjoy these video picks inspired by your resolutions. Let's start with a resolution from one of our more clever Patreon patrons, Patrick Gilmore, it's pretty much guaranteed to meet his goal of eating more sugary, carb-loaded food. We have a video for you Patrick, and for the rest of us who are maybe wanting to eat less junk food, here's a video explaining why this can be such a difficult goal. Enjoy and good luck.

 Why Our Brains Love Junk Food  (1:11)

Carrots. Or French Fries... How are you feeling about this choice - Be honest. Which would you rather eat? That's what I thought. 

Humans love fats and carbohydrates. Why? Well, because they have a lot of energy in them and energy's what we need to do all of the stuff that we humans do. But, we're omnivores. We can get our energy from meat, grains, vegetables, nuts, tubers, fruit - we're extremely versatile animals, compared to like a cow, which is pretty much stuck eating grass, or a lion which has no business eating anything other than raw meat. 

So if we can get calories from a bunch of different kinds of food, why, at a very basic level, do we really just wanna eat fats and carbs? Well, it has a lot to do, apparently, with our evolutionary history. Let's start with a member of my extended family, grandma Australopithecus. This pretty lady was a direct ancestor of the first member of the genus homo.  She was different from us in a lot of ways: her brain was 35% the size of ours, her stomach was a lot bigger, and her teeth were larger, flatter, and duller. All of this leads us to the conclusion that Australopithecus ate mostly fruits, vegetables, and tubers. But raw fruits and vegetables, especially before the agricultural revolution, weren't very high in calories, and if that's all you're eating, it takes a big, patient digestive system to process that. 

So if your body's working really hard all day to squeeze every last calorie out of your not-very-energy-rich-food, something's gotta give, and for Australopithecus, it meant having, ya know, kind of a tiny brain, because brains require lots of calories. 

It wasn't until Australopithecus' direct descendant homo habilis came along two million years ago (about the time Australopithecus went extinct actually) that we start seeing smaller, more efficient guts, smaller teeth, and brain about 50% bigger than Australopithecus. These clues, coupled with the fact that this is around when habilis began to control fire, suggests that they were able to cook. And that means they were suddenly able to eat meat without worrying about dying of nasty festering meat disease, and they were suddenly able to unlock all sorts of hidden delicious energy from the vegetables that are pretty stingy when they're raw. 

So since then every species in the genus homo from habilis to homo sapiens have had larger and larger brains, thanks in part to increasingly high-energy diets. These huge brains of ours are expensive, and we've needed a bunch of fat and calories for them to evolve, not to mention just to maintain them. 

So because our brains are not stupid, they've evolved to love the crap out of high-energy food. And now look at us, we can eat a donut-hamburger whenever we want to because we're the kings of the freakin' earth. And our brains, they're like, "yeah!" In fact, some studies have revealed that eating high-fat food not only activates our brain's pleasure centers, it also activates the touch centers. So our brains respond to eating fatty, high-calorie foods the same way we respond to hugs from our moms, literally comfort food. 

But even though our brains are totally pumped that grocery stores are now packed full of sweet, sweet snickers bars, the rest of our bodies are like, "I'm so tired of dealing with all of this nougat, help us!"Which is why, even though the carrot doesn't look as good, you should eat it. Your body will thank you. 

Thank you for watching this episode of SciShow, if you have any questions or ideas or comments or thoughts for us, please leave them down below, or on Facebook or twitter and if you want to continue getting smarter with us, go to and subscribe. This episode brought to you by nutritious things... not by fries... just to be clear.

 3 Terrible Old-Timey Ways to (Not) Lose Weight (4:26)

Hank: Eating better is a popular New Year's Resolution, but so is exercising more. A lot of you told us that you're training for races or have weekly exercise goals to make. It sounds like you all have realistic ideas about how to reach your goals, but here's a video about some weird ways that you definitely won't lose weight or tone muscle.

Michael: If you spend time on the internet, you probably see a lot of ads.  After a while, you might notice that some ads show up everywhere.  Like you've probably seen something along the lines of this one: "Lost weight with this one weird old trick!  Doctors hate this!"

It turns out that those kinds of ads are really old, like older than the Internet even.  As far back as the 19th century, companies were advertising all sorts of strange ways to shed fat.  And from so-called sauna pants to electric shockers to vibrating belts, you'll sometimes still see them presented as a way to lose weight.

They make tempting promises - just stand around, let the machine do the exercising for you!  But these methods aren't exactly effective because the supposed science behind them isn't quite so scientific.

Take the sauna pants, for example.  The idea was that you'd make some part of your body really really hot, sweat a lot, and somehow get skinnier in the process.  But all you were doing was dehydrating yourself.  

There were a lot of different versions.  Some advertised in the 1970s were like giant inflatable balloons for your body.  Others were heated electrically and, for some reason, you can still buy them though they aren't generally marketed for weight loss anymore.

If you've ever imagined pants made out of an inflatable mattress, you can probably imagine that it was indeed REALLY hot in there.  You would sweat a lot.  And of course if you weighed yourself before and after you tried this, the numbers would totally go down on the scale.  

According to the ads, this meant that you were losing what they called water weight, which is technically true.  Wearers of the pants lost some weight through sweat, and sweat is mostly water.  
But that's essentially the same thing as saying that peeing is an effective weight loss method,!  Unless you plan on staying dehydrated forever, it comes right back the next time you drink.

Electric shocks were also once all the rage, and you'll still see these electronic muscle stimulation or EMS devices for sale, claiming to give you rock hard abs or whatever.

But while they might be able to make your muscles firmer, they aren't going to burn much fat.  Normally, signals from your nerves releases lots of charged ions in your muscles, making them contract.  So when you apply an electric charge with an EMS machine, those muscles think your nerves are sending them a signal, and they contract like crazy.  

And that does exercise your muscles, which have to use energy as they contract and then relax.  And in some cases, the repeated contractions have been shown to make them firmer over time.  

But since it's just a few individual muscles moving, instead of your whole body working together, they don't use very much energy.

One study found that a 75 kilogram person using an EMS device for an hour might be able to burn 76 calories total, but if that person decided to walk around for an hour, they would've burned 326 calories.

Which is why, at least in the U.S., the FDA won't approve any EMS device that claims to help with weight loss.  And even the approved versions can cause burns, so you might just be better off doing your crunches manually.

And now we come to the fat jiggling belts.  They promise to loosen fat, which your body would just flush away, though no one ever explained exactly how.  And that's not how fat works.  You might be able to shake it off, but only because you're burning off fat as you shake and definitely not if something else is doing the shaking for you.

Movement takes energy, and normally when you exercise that comes from the energy stored in your cells.  Eventually your body starts breaking down the chemical bonds and fat molecules to get that energy.

But in the case of fat jiggling machines, the energy was coming from the electricity powering the machine, not your fat cells. There are ways to make your body "flush away fat" like a cosmetic procedure that kills fat cells by freezing them.  And other body-shaking techniques like chairs that swivel back and forth while you sit on them work by forcing your muscles to compensate for the movements.

But you can't just detach your fat cells by moving them around a little bit.  Exercise only burns fat if your body is breaking it down for energy.  So if that's a thing you want to do, you're gonna have to put in the work yourself.

  How Many Calories Should I Have in a Day? (8:10)

Hank: So now that you know some good exercise regiments to avoid, here's a couple videos with Michael Aranda about appropriate calorie intake, and when you burn fat, where does it actually go?

Michael: How many calories should I have in a day? You’re probably asking because you want to know how many is too many. After all, you know that if you take in more energy than you need, your body will store that excess energy as fat. 
But before we can talk about how many calories you need, let’s start with what a calorie is. The calories that you find on food labels aren’t the same as what scientists call calories. In chemistry, a calorie is the amount of energy it takes to raise the temperature of one gram of water by one degree Celsius. But the calories listed on your can of soda are actually kilocalories -- each one equal to 1,000 of the “small calories” that chemists use to measure energy.

So when your soda pop says it has 150 food Calories -- you’ll notice it’s written with a capital C -- that’s the same as 150,000 small calories -- with a little c. So that’s enough energy to raise the temperature of a whole liter of water by 150 degrees. Kinda puts things in perspective. 

But how many calories you need depends on who you are, and how you live your life. First, there’s your age to consider. Despite the stereotype of the ravenous teenager, your calorie demands actually peak when you’re in your mid-20s. That’s when your metabolism is higher than at any other point in your life, and because you keep growing into your 20s, once you're done, you have more lean muscle mass which requires more energy to maintain. So, depending on your lifestyle and other factors, when you’re in your 20s, you may need from 2200 to 3000 calories a day! Your sex is a factor, too. Men tend to have more total body mass, and more muscle mass, than women on average, so their caloric requirements can be slightly higher.
According to the US Institute of Medicine, the average calorie range for an adult woman is 1800 to 2400 calories a day; for men, it could be anywhere from 2000 to 3000. But that’s obviously a pretty broad range. And as delicious as it sounds, most of us don’t need to be eating 3000 calories a day. And that’s because the most important factor, by far, that affects your calorie needs is your activity level.
For example, if you’re a woman in your 30s or 40s, and you live a rather sedentary lifestyle -- meaning you don’t set aside time for any exercise -- then probably don't need any more than 1800 calories on average. But if you regularly take a nice brisk walk -- say between 2.5 and 5 kilometers a day -- then your caloric needs go up about 10%, to 2000 calories. And if you regularly walk more than 5 kilometers -- or burn the equivalent amount of energy doing some other exercise, like running -- then you’re looking at another bump, up to 2,200 calories. 

But when it comes to calorie intake, medical professionals will tell you that the real goal is to focus on your energy balance -- that’s the balance of calories you take in compared to the calories you burn through physical activity. So, naturally, if you burn more calories than you take in, you’re going to have to use more of the energy that you have stored up as fat. And, on the other hand, if you consume more than you use, you’ll just keep building up those “energy reserves” around your midsection. 
Since no one burns the same exact number of calories that they eat every day, the key is to maintain energy balance over the long term. So if you consistently ingest more energy than you use, you’ll be out of balance -- just as you would be if you keep burning more energy than you supply for your body. But, if you ask me? You look fantastic.

 When You Burn Fat, Where Does it Go? (11:13)

There are some things in life that, when they're around, we wish they weren't there and when they're gone, we're just glad they left. For many of us, one of those things is fat. But your fat tissue is full of important biological molecules called lipids, long, stringy compounds of hydrogen, carbon and oxygen that are great at storing energy in their chemical bonds. 

When the molecules are broken apart, they release the energy stored in their bonds. We often refer to this process as "burning fat". But when you burn fat, where does that material - the actual stuff that jiggles around and cushions you and insulates you - where does it go?

Interestingly enough, a recent survey of doctors, dietitians and physical trainers revealed that even the experts in fat loss didn't know the answer, although they thought they did. More than 50% of the respondents thought that, when you burn fat, all that mass is simply converted into energy and lost as heat.
It's a common misconception but it's not possible.

I mean, just because you don't like something doesn't mean that the laws of chemistry don't apply to it. And one of the basic principles of chemistry is the conservation of mass. This just means that the same amount of material always comes out of a reaction as goes into it. 

Even if that reaction happens to generate heat, you'll wind up with the same number of each kind of atom that you started with. 
So when you break up those lipids in your fat cells and release their energy, all of that hydrogen, carbon and oxygen in those molecules will still be there afterward. But if you burn a lot of fat, and it's not there anymore to hold your pants up or whatever, where did the mass go?

Turns out, you exhaled it. Biologists at the University Of New South Wales recently did an atom by atom breakdown of where the mass of your fat goes after it's burned in your body. They found that for every ten kilograms of fat that you burn, you have to inhale 29 kilograms of oxygen to metabolize or break down the fat and release its energy.

And the process of breaking down that much fat produces 28 kilograms of carbon dioxide and 11 kilograms of water.
So for every kilo of fat that you burn in your body, more than 80% of that mass is lost as carbon dioxide that you breathe out.

The other 20% you lose as water, in your urine, your sweat or -depending on how hard you work out - your tears. 
But, if you do the math, you'll see that all the mass in that fat-burning reaction has been conserved. Ten kilos of fat plus 29 kilos of oxygen equals 39 kilos total, and together they produce 28 kilos of CO2 plus 11 of water, which also equals 39 kilos. 

So remember that the next time you're huffing and sweating on a treadmill or walking your dog or really doing anything that makes your body call on its energy reserves. You're basically just emanating fat through your breath and your skin, but in a good way.

 The Science of Hangovers (13:30)

Hank: Alright, We've talked about diet and exercise, but what about drinking less? This next video is about the science of hangovers.

What do fried canaries, pickle juice, Coke mixed with milk, Vegemite, boiled tripe and coffee have in common? Well in addition to being frickin' nasty, except for the coffee, they're all purported folk remedies for a hangover. Most adults who partake of alcohol have experienced at least one, or two, or three, or fifty dozen hangovers in their lives, and by all accounts it sucks. Terrible headaches, nausea, fatigue, dizziness, that feeling of your eyeballs wanting to fall out of your head. But how does this stuff work? Well, it involves three really miserable interacting things. 

The first step of the hangover is the biggest cause of your misery: dehydration. Booze is a diuretic which means it makes you have to pee, which is why there is always a line at the bathroom in a crowded bar. Alcohol suppresses the pituitary gland's release of vasopressin, the hormone that triggers the re-absorption of water back into the body. Without it, the kidneys just send the water straight to your bladder and into the john. Headaches follow when the body desperately resorts to stealing water from the brain, causing the tissues to shrink and pull away from the skull. Meanwhile, all that peeing causes you to lose a lot of sodium, potassium and magnesium which are all necessary for proper cell function. 

Step two: acetaldehyde overload. Our bodies metabolize alcohol in two phases. First, liver enzymes break down the actual alcohol in the drink, called ethanol, which creates a toxic byproduct called acetaldehyde. The acetaldehyde is then attacked by more enzymes and a peptide called glutathione and is soon reduced to harmless acetate. This works fantastically if you're drinking small amounts. But if you're guzzling pints all night, eventually your exhausted liver can't keep up and all that toxic acetaldehyde starts to build up making you feel really crappy. 

Step three: the congener connection. In addition to alcohol ruining your body's ability to hold water and creating toxic leftovers for your liver to handle, most drinks also contain congeners. In chemistry, this refers to any group of related chemicals. But in this case, when we're talking about alcohol, it has to do specifically with chemical impurities that form during fermentation and aging of alcoholic drinks. They provide flavor and color, but they also contain some of the same toxins that give your liver trouble, like acetaldehyde, esters and acetone, aka paint thinner. Darker drinks like brandy, bourbon and red wine have more congeners than clear spirits like vodka and gin. 

But, if you're over 21 and currently hungover you don't need me to tell you why you're experiencing such a terrible experience, you just need me to tell you how to make it stop. Fact is, none of folk remedies I mentioned earlier are going to help. Coffee may help relieve a headache by shrinking the blood vessels in your head but it will also continue to dehydrate you. And don't reach for the hair of the dog, because that just prolongs the inevitable.

Replenishing sugars and minerals with a sports drink or a nice salty banana isn't a bad idea, but if you ask any doctor they'll tell you the only sure cure for a hangover is time. It's time the afflicted can spend re-hydrating, eating, sleeping and thinking about making better choices. And of course, the one foolproof way to avoid a gnarly hangover: don't drink so much. 

 5 Weird Reasons Not to Smoke (16:35)

This last video speaks to a pretty classic New Year's resolution, it's a hard one, but one of our Patreon patrons, Alexandra Adcock, accomplished it in 2015, so have heart. If you're trying to quit smoking, it can be done, and if you don't smoke, enjoy this video all the same. Here are five surprising weird reasons not to smoke. You know, besides the obvious ones.

We all know that smoking is bad for you. There's even a possibility that there was a horribly frightening advertisement before this video featuring some person who talks through a hole in their throat. You shouldn't smoke, and you know the reasons why. Or do you?

There are in fact some really surprising and weird reasons not to smoke in addition to all of the normal horrible ones and we're going to talk about a few of those now.

Number one. Smoking makes your boobs sag. That's right. Boob shagginess is a real scientific studied thing and among the risk factors are being overweight, having larger breasts, having babies and smoking cigarettes. Things that do not affect boob shagginess whether or not you breastfeed, weight gain during pregnancy and lack of upper body exercise. So now you know!

Two. Like listening to music? Watching movies? Hearing things? Smokers are 70% more likely to develop hearing loss than non smokers. Even worse: development of hearing loss in smokers happened much earlier than in the general population. Smokers start losing their hearing in their 40's or 50's instead of their 60's or 70's.

Number three. If you're not worried about saggy boobs because you don't have any boobs allow me to scare the cigarette right out of your mouth. Men who currently and formerly smoked were about 30% more likely to suffer from impotence. While you, and maybe even your lady friend might think that that cigarette sticking out of your mouth makes you look super sexy, it's not going to matter if you can't get it up.

Four. If you don't care what you look like or whether you can get it up and you don't have any kids and you live alone with a bunch of dogs and cats, think about their health. Second-hand smoke has been proven to cause nasal and lung cancer in dogs and malignant lymphoma in cats. This might seem inconsequential compared to the human health risks but 37% of smokers said that clear evidence that smoking was bad for their pets would motivate them to quit.

And finally, number five. You like being happy? In a study of more than seven thousand adults smokers were found to be less happy than non smokers and ex-smokers who had quit more than one year previously. Healthy body healthy mind I suppose. Too bad those things are so freaking addictive. My strategy which has worked for me thus far is to never let one of those things anywhere near my mouth. I suggest you try it too.

If you need that extra kick in the butt or just a sympathetic voice, I hope these videos have helped, and thank you for sharing your New Year's resolutions with us, one of our goals for 2016 is to make more SciShow videos a week. Maybe five videos, maybe six, maybe seven, what do you think? Let us know in the comments below and if you want to help us make those extra videos happen, you can go to and of course, happy belated New Year.