In regard to careers and body types of sims

@iamsuebert I understand that some of these aspects can be rather grinding in-game, especially at some 'points in life'. If you don't mind, I thought I would add here a few things I o in gameplay with my sims that may address some of what you are dealing with and finding frustrating?

• If your sim begins to get too buff or too fat and you don't want to deal with workouts, you can go into the CAS and 'sculpt' the sim - press inward at the waste, for instance, to reduce waste size or muscle size on arms/legs, etc... Then...
• I normally add one or two treadmills to the lot (if two are side-by-side they can talk at the same time and increase social. Have them do a workout every day or two for a while and they seem to get into the habit. I find that many of my sims (especially if they have an 'active' trait) will get on the treadmill here-and-there on their own and maintain their form and seem to enjoy it also, after they're used to it. (At a certain fitness level they also get a 'no sweat workout' option, which is great. You can also buy the 'gym rat' reward and then they don't have hygiene decrease by working out. After these things are in place, and they don't take that long, weight tends to be a non-issue.
• I normally play with aging off, or at least until you get through the grind of completing the lower-level, more difficult career challenges.
• It helps to add other sims to the household for support and so they don't have to do/pay for so much to enjoy decent food/lifestyle/career-prep items. Hint: don't add them in the initial household. Create the roomies all as their own separate households then one-by-one add them to the household with your sim and save after adding each one. This way your new sim brings their initial $20,000 to the household, and you have the money as a group to own a decent home and get the items for it that you each need for your career/goals/comfort. 
• Have at all sims earn at least one cooking skill point so no one burns the house down because they're hungry, but I usually have a couple of sims in the household get good at cooking (and use it for a career for one sometimes) and cook a couple of big meals a day meals - add to the refrigerator and they can all just grab leftovers as needed.
• Have one or two sims get really high handiness skill (some careers use this also) and have them upgrade and fix. Some of the upgrades are really helpful.
• Get a maid. Who needs all that cleaning worry. It doesn't cost much and then you don't need to worry about any of that stuff. If you clean everything she just does not come for the day or only for what is needed, which is brief if you do some cleaning also. Have a neat sim and they will likely do most if it anyway.