Most efforts to lose weight are only temporarily successful (unless using medicine or surgery).
Weight science is awful, so grain of salt here, but: losing weight and gaining it back is thought to be more harmful than maintaining a constant weight, especially if either of those was fast. It’s probably still good if you get to a new lower trajectory, even if that trajectory eventually takes you to your old weight, but usually when I hear about this it’s dramatic gains over a fairly short period.
People will probably bring up the claim that low calories extend lifespan. In the only primate study I’m aware of, low-cal diets indeed reduced deaths from old age, but increased deaths from disease and anesthesia.
I think some of the reduction just comes from being lighter, which is inconvenient but not a problem. But it does seem like people who lose and regain weight have a lower BMR than people who stayed at the same weight.
Because when you lose weight you lose a mix of fat and muscle, but when you gain weight you gain mostly fat if you don’t exercise (and people usually don’t because they think it’s optional) resulting in a greater bodyfat percentage (which is actually the relevant metric for health, not weight)
Weight science is awful, so grain of salt here, but: losing weight and gaining it back is thought to be more harmful than maintaining a constant weight, especially if either of those was fast. It’s probably still good if you get to a new lower trajectory, even if that trajectory eventually takes you to your old weight, but usually when I hear about this it’s dramatic gains over a fairly short period.
why is it bad to lose/regain?
An incomplete and poorly vetted list:
calorie counting[1] or restrictive diets:
harder to get a full swath of micronutrients
osteoporosis
fatigue
worse brain function
muscle loss
durable reduction[2] in resting metabolic rate
weakened immune system
generally lower energy
electrolyte imbalance. I believe you have to really screw up to get this, but it can give you a heart attack.
stimulants
too many are definitely bad for your heart
excess exercise
injuries
joint problems- especially likely at a high weight
ozembic
We don’t know what they are yet but I’ll be surprised if there are literally zero
Problems you can get even if you do everything right
something something gallbladder
screws with your metabolism in ways similar to eating excess calories or fat
increase in cholesterol
chatGPT says it increases type 2 diabetes. That’s surprising to me and if it happens it’s through complicated hormonal stuff.
Regain: everything bad about high weight, but worse.
People will probably bring up the claim that low calories extend lifespan. In the only primate study I’m aware of, low-cal diets indeed reduced deaths from old age, but increased deaths from disease and anesthesia.
I think some of the reduction just comes from being lighter, which is inconvenient but not a problem. But it does seem like people who lose and regain weight have a lower BMR than people who stayed at the same weight.
Because when you lose weight you lose a mix of fat and muscle, but when you gain weight you gain mostly fat if you don’t exercise (and people usually don’t because they think it’s optional) resulting in a greater bodyfat percentage (which is actually the relevant metric for health, not weight)