Whoa

>fat character gets more HP
Is there a not bullshit reason to make it work?

I think it would be fine as long as the stat governing it isn't the same as the one detmining how much the player can exert themselves, and unfortunately it often is.

There's more meat for the bullets to move though before they hit something important

well, HP = meat point works succinctly here doesn't it?

Padding.

As a former fatso i can attest that you can absorb more blows. Still hurts though.

To be fair, blubber won't help for shit if you get attacked with a dagger or gun.

it actually does.

In GURPS HP is actually equatable to mass, they even use HP to calculate stuff like collisions and falls.

That really depends with a knife. For your average fluffy fellow, it will only offer as much protection as misjudging where to put a slash can create. Blunt trauma will be a lot less direct in the torso though. Now, if the PC is trapped within the prison of their own fatsuit, that's enough that even after being compressed violently, the hilt of a knife getting caught on the sheer volume of fat will penetrate muscle and vital tissue by cm's instead of inches. If your muscles are shit even underneath the fat, you won't stop near as much punishment to your organs. It's enough to defend significantly from small blades and shallow points, teeth and nails, a lot if blunt abuse.
The other important variable is that fat is fuel, as well as a component in expending energy in addition to storing it. I'm a lean little fuck with an active job, and I get to eat 5-10kcal a day while gaining minimal weight, but I do occasionally get a few lbs of belly, back and ass fat. Not really a problem lugging it around, I only feel the difference in a dead sprint. But I can do a 60 hour work week with that 5-15lbs of fat on me, then go do another week or two before I feel remotely burned out on energy (although the joint and muscle pain will be real). Let me work that overtime when I am already lean though? My body will feel like shit in a hurry. It only takes two days of work in the busy season before my elbows and back want a week of rest if I haven't been gorging 2kcal meals all day, with over 100g of protein. Fat me can handle it while skipping a meal every other day though. And fat me is still a beanpole who makes average girls whine about why I get to be so skinny. Granted, if you don't lead at least a semi-active life, your body will signal itself to conserve energy, and it will feel like you are sandbagging yourself because your body is being stingy about priming itself to release and expend energy. Unspent sugar in the bloodstream is detrimental.

It's also really important to note; taking a hit to a small slab of tensed muscle like pectorals or a thigh does still hurt, but so long as the hit wasn't going to require months of recovery anyways, you can take it from something you have every right to be pissed off and want to punch face over, down to just enough to make you wince. You might feel it for minutes instead if half the day. And that tensing requires energy. Tense your whole body for half the day, and the difference will be noticeable on a larger scale. Fat will mean fatigue will take longer to set in due to being out of fuel, so as long as your PC can run a few miles more than once a day, their fat reserves will decide when they'd be too pooped to do anything else that day, rather than their lungs or heart. Orrrrr they could just have their body metabolize their muscle instead. The fat that pads their internal organs in the chest cavity and the brain. You don't want /any/ of that, especially the last. The last one means you're gonna die today if you don't fucking stop and fill your fucking face. I don't recommend that. Starving to death blows, but dying while starving, moving vigorously, and being light headed from lack of energy, to the point that you're about to pass out? That shit blows. It means you died because your body can't metabolize anything substantial enough to kickstart even minimal organ function, and I promise, you can feel your body saying "I started breaking down a long fucking time ago, fucking stop or die already" well before your lungs and heart stop pumping and your brain goes foggy then consciousness just evaporates into nothing more suddenly than it can process its own organ failure.

if they're more of Samoan musclefat instead of average American blubberfat, then yes, it is justified. Thick, solid fat is better than the blubbery, fluidish fat.

Technically it does
Gladiators used to be put on highly carb-based diets that made them gain weight and appear more physically imposing, and having extra body weight made knife slashes less dangerous since padding allowed them to bleed but theres a lower chance vital organs will be harmed

yeah, this is always the problem. You have all those typical huge fat guys with heavy weapons who are tough, strong and slow but you can't make a character like that with the existing rules.

You have to be fit as well. The people in strongman contests all have a healthy protective layer of fat on them. Wrestlers gradually get that too if it's been a while since they've had time off (purely working out at the gym gets rid of it, but it's not actually your natural state).

The problem with the typical north american blubbard, those who screech about "fat-shaming" and the like, is that they are nothing BUT the fat. So while sure, they can take a blow, any mechanics that merely give advantages to someone THAT big needs to keep in mind that once you reach that state of affairs, your cardiovascular's more or less already stressed the fuck out, half your own body weight's infringing on your encumbrance level, and while yeah you'll be harder to critically stab, there's more of you TO stab, and you can just cross out the place where it says "reflex" on your sheet and write down "NO".

Also fall damage increases: My aunt for example is similar to op's image, and snapped her fucking ankle when she accidentally skipped a step. Mind you she's in her late 50s, but fucking think about it. She went down TWO stairs with one foot instead of ONE stair, and F=MA fractured her fucking foot. As an adventurer in her 30s a five foot drop would probably have been enough.

RE: the 5ft drop, depends on how rotund she was, and her health at the time. But you did say adventurer, so let's call it that... On a nat1 for falling, I could believe it would end her mobility if she landed all on one leg with everything I'm the chain reaction of the rest of her pushing down on her ankle was particularly unforgiving. She could snap her neck, crack her skull mightily, break an arm or leg or obliterate the shit out of a joint, fracture ribs...
On the other hand, I have had friends and coworkers of the 240+lbs persuasion with relatively admirable fitness. If they lead an active and concussive life, my money is on them being able to be proactive enough about falling 5-10 ft to suffer little more than bruising, provided they fall onto a flat surface, even with it being tile/concrete. That shit will hurt, but a body that has grown accustomed to being tested can be incredibly sturdy.

It does if it keeps the dagger from ripping up a vital organ. You can heal from a deep puncture if it doesn't get infected, but you're not coming back from torn intestines.

>Is there a not bullshit reason to make it work?

Could be a fun game mechanic if you're going the "race=class" route and you're playing an Ogre.
Ogres, naturally, being all about eating lots n' lots, bulking up, so they can be fat and in charge.

If you're in shape your mass can go up fast actually. Muscle's rather dense. Wife was 5'5 yet weighed around 150 in highschool because she was trying to go pro cyclist.

The difference is between someone like Kingpin, versus "my 600lb life". One of them has like 18 strength and enough of a skeleton that technically he's just somewhat chubby, while the other can barely make it to the krispy-kreme and back and calls it a day for exercise.

>your fat character gains a bonus to HP!
Yay awesome!!!
>and you have diabetes
... fml.

Fall damage is hugely dangerous for anyone who's heavy, regardless of the source of the weight. Bodybuilders will get WRECKED by fall damage because they've got the mass but not the padding. Since bodybuilding inherently reduces the flexibility of all of your joints, it can actually be a significant problem if they don't have good balance.

>bodybuilding inherently reduces the flexibility
You don't Yoga between lifts brah? This is 2017

The reason that bodybuilders do yoga...
is because bodybuilding inherently reduces your joint flexibility. Even so, it's a net loss, usually the flexibility training is just a stepping stone to get more bulk.

Yes

I honestly don't even see how people can get so fat they can't move or exercise in the first place. I suppose a part of it is like people said with lardbeasts that are all fat with 0 muscle, I saw a pic of some guy who looked like Jabba the Hutt that was labeled "395 lbs", like this niggas belly fat was enough to cover his dong, while I weigh about 385 and still wear a 1x or 2x shirt comfortably and the closest thing I even do to exercise is haul my fat ass around at work and occasionally help move heavy things because I can lift more than the majority of my friends.

It just seems to me like you have to physically TRY to get that fat, because when you weigh that much just walking to the store is carrying a hundred pounds of weight on your shoulders.

Really I'd say it depends on the system's use of hp. If it's simply how much blunt/slashing/piecing damage a person can take then there are obvious answers as stated above. And sometimes good system will take that into account with things like exhaustion or fatigue or lower shit like dexterity or whatever. Other systems that don't use hp like that will make it matter when people get hurt or try nimble things that a fat person shouldn't be able to do as well as a skinny person. But my personal experience is that I'm fat and I can take a blow better than just about anyone I know.

I have six uncles (dad was one of 11 kids) who are kingpin-sized. Dad was 5'10" himself and was always 180-240lbs when in shape even at 80. The uncles run 6'3 to 6'7 or so, never actually measured the taller ones but I'm an ant next to them. Between age and size they all struggle to get into sedans or even some SUV's. On the weight and fitness side, some are fitter than others but they're all soundly under 28%bf. I don't think a one is under 250lbs, and I know more than one is over 300lbs, I could even believe a whopping 400lbs. Fuckers are built like vending machines, and they can put away food like one too.