Rule of threes is fun but try not to let it go beyond two for those -- you might survive but permanent damage is very much on the cards and even if not there will be a recovery time.
You can expand some of those (deep sea diving for instance can be quite a bit longer, and some tribes/villages that do dive a lot have some adaptations on that front) and environmental conditions will impact things as well as activity levels -- manual labour on a building site in a hot desert and 3 days is nowhere close for water, sitting in a temperate alpine cabin and that changes.
Similarly you might not be diabetic but lack food and water and you will start to make mistakes, lack focus, tire very easily and feel awful, especially if you are doing manual labour, physical endurance and heavy moving tasks.
Combining a few of those and it gets more fun again -- food takes water to digest so unless your food happens to be mostly water then consider starving for a bit until you get there.
As above if you are in a first world country this is unlikely to be the case outside of disaster, shit hits the fan, without rule of law/wrol. Fairly far from most of those, though disaster is one to note and if you have to walk out of somewhere then that can be hard on things (a decently fit adult should be able to do 30 miles/45km in a day, and again the next. It will suck but it is doable. Push bikes are good things too. Looking around at most of the adults I see from countries that make up the majority of the users here then that kind of distance is probably a fantasy). Peanut butter is cheap (cashew, almond and pistachio less so but similar properties), lasts for ages and seriously calorie dense if you need to have something in a bag to grab, though do yourself a favour and mix some cinnamon/ginger/cardamom/whatever spices you like in.
On not eating. 24 hours without food, and just plain water, is often noted as resetting your sleep schedule if it is out of line -- thought being if you are doing the whole savannah dwelling ape 10000 years ago thing then time between kills might change things.
On being fat and not eating. Be aware it is actually on the dangerous side for some things there. If your body is digesting some of the more long term fat stores then it is not great, granted digesting muscle is not much better. Or if you prefer there is a reason it is called diet and exercise.
If lack of food is more going to be lack of funds (and inflation is fairly impressive right now, cost of fuel and food being part of that) then learn to cook*, learn to cook well (I like a steak more than most but they are expensive for a reason, less choice cuts and organs** can still make some delicious stuff though if you take the time to actually make it), preserve things, grow some things (northern hemisphere is just about still in planting season for some things, or if you can find some established stuff then go that, window boxes are a thing if you are in a city), figure out when the "get it out of my shop" reductions happen (and preserve those), if shops throw things out (some places have mandates that all frozen/chilled stuff needs to go upon loss of power for more than 10 minutes or something***), learn to forage (wrong time of year for a lot of things but spring vegetables are a thing) and hunt or fish if that is a thing for you. Hopefully you don't have any old or young depending upon you.
Do also learn about nutrition in general -- might get all the calories you like but getting scurvy or beriberi (or one of a thousand other malnutrition based illnesses and weaknesses) is not going to do you well. If you are doing exercise then salt is usually the first one to be immediately obvious.
*might as well do budget cooking
**you are more likely to catch me missing steak night than you are liver (+ bacon but I don't like bacon) and onions night. Granted I go for lamb liver rather than beef or chicken.
***I remember seeing in the US a while back some shops chucking food out because their freezers lost power... because of a snow storm that deposited shin high snow everywhere (hint - snow is very good at keeping things cool). Power outage trackers are a thing as well.
As far as the personal question. I used to go swimming a fair bit and could hold my breath for quite a while, probably still could but have not gone swimming in years at this point. Drinking. Rarely more than 12 hours and that is usually poor planning on my part (making sure I have a drink being a fairly high priority). Eating. Occasionally will go 48 hours without for fun. Have done things like 600 calories when burning 6000 (do some decent hill walks and you can get there easily enough) as well, which was less fun but a lighter pack/some more comfort is a perk of not having to carry as much food or cooking gear.
