it can seem like a hype factory design more generate clicks then to generate

understanding people want to hear what to eat and what not to eat in order to

be healthy

the problem with that is that it's complicated it's too complicated to fit

into a headline eating lots of fat will make you unhealthy but so will eating

lots of anything studies show that cutting fat intake is useless when

attempting to help people lose weight if those calories are replaced by something

else which they tend to be

now that is relatively straightforward chemically but it's boggled dietary

scientists and especially journalists writing about it for decades but the

basics of what we understand aren't that complicated

so let's get to the heart of fat

fats are molecules that organisms used to store energy they are very good at

that and so they can be converted into lots and lots of energy for running an

organism

whether it's a seed growing into a plant or a neuron firing in your brain

but basically the first thing to know about fat is that it is energy dense so

per gram of fat has more than twice the energy of protein or carbohydrates

that's like everything we eat are made of chemicals and those chemicals are

primarily composed of long chains of carbon atoms each of those carbon-carbon

bonds can be broken by your body and converted into usable energy the energy

density of fat combined with the fact that people who ate high-fat diets tend

to be less healthy was the original cause of the anti-fat craze that started

in the sixties and continues at least to some extent today but it turns out that

fats are not inherently bad for you indeed they are an absolutely necessary

part of the diet but there are definitely some fat that promote health

more than others and some that are downright dangerous

you've heard of the main categories get to trans saturated or unsaturated

hydrogenated polyunsaturated omega-3 all of these words are chemistry terms that

get talked about a lot without discussing what they mean like at all

but this is a show so let's go there carbon has four unpaired electrons so

each carbon likes to bond to 4 other things this is methane carbon bonded to

four hydrogen's and yes I'm using snatam Barrett a Siam's molecular modeling kit

which I'm really excited about if the carbon is in a saturated carbon chain

two of those things will be other carbons unless it's the end of the chain

and two of those things are going to be hydrogen if this is what the carbon

chain looks like with a bunch of carbon atoms each bonded to two carbons and the

two hydrogen's that is a saturated fat which tend to be solid and are mostly

made by animals though also coconuts the thing that saturated fats are saturated

with is hydrogen

every carbon is bonded to two of them except for the last which is bonded to

three and unsaturated fats are not saturated they have fewer hydrogen's how

they've got at least one double bond between two carbons in the chain each

double bond means to fewer hydrogen's so unsaturated fats don't have as many

hydrogen's as they could have / carbon atom and this is not as minor a change

as it might sound single bonds can rotate around their axis no problem but

double bonds lock a structure into place and that double bond can either lock the

chain into a kink or lock it straight in nature a double bond in a fat chain

almost always

locks it into a king this prevents the fat molecules from stacking into

lattices making them more likely to be liquid at room temperature so

unsaturated fats tend to be liquid making them oils and come mostly from

plants and fish the case configuration is called the cis isomer

and the straight one is the trans isomer what isomer just means

that the molecules have the same chemical formula but are different

shapes and the different shapes matter a lot

saturated fats are less healthy than unsaturated fats because they packed

together easily and conform plaques in your arteries and can also interact with cholesterol

making it build up in your bloodstream cis unsaturated fats which

the rest of the world just calls unsaturated fats don't stack well and so

don't form plaques so that difference exists but it isn't as big as we used to

think it was it turns out that our bodies are pretty good at dealing with

whatever we throw at it as long as it's fairly familiar worse by far are the

trans unsaturated fats

these are almost all manufactured by adding hydrogen's or partially

hydrogenated some unsaturated fat like soybean oil so trans fat and

hydrogenated fats are the same thing

one refers to the process through which they are created in the other their

chemical structure

these are fat that have double bonds and stack well in fact they stack even

better than saturated fats and our biochemical systems are designed to

break them down and they interact badly with cholesterol a two percent increase

in daily intake of trans fat corresponds with a twenty-three percent increase in

the chance of heart disease amazingly they were initially seen as a healthy

alternative to saturated fats and are now in the process of being completely

banned in America now even inside these categories there's a ton of variation

and inside that variation comes more active areas of research which is less

known for sure

polyunsaturated fats are fats with more than one double bond might be more or

less healthy than monounsaturated fats no one really agrees because they both

have benefits and drawbacks and it matters where in the chain the double

bonds are you should probably have some of both

and if the double bond is just before the third carbon from the end we call

that an omega-3 fatty acid and they seem to have a wide range of benefits they

are also one of the two essential fatty acids the other being omega-6 essential

compounds are chemicals that our bodies need to function correctly but can't

manufacture on their own so we literally need to eat those kinds of fats in order

to survive and indeed we need to eat fat in general to survive it's good

for you in the correct quantities so those are the basics of fat you guys

they have tons of energy in them so they're great when you need calories but

they also make it super easy to eat too many calories they are absolutely

necessary for life they taste good and are good for you but unsaturated fats

are better and trans fats bite very will kill you thank you for watching this

episode of scishow which was brought to you by our patrons on patreon if you

want to help support the show you can go to patreon.com/scishow

and if you're interested in statins i'm not sure if the Kickstarter is still

going on but they're basically these little magnetic modeling guess they're

very cool we'll put a link in the description

yeah