Weight loss when going from very high calorie intake to normal one…

[AeroBCD]

Sorry if this is a stupid question, but both short term and long term, what kind of weight loss would someone see if they cut down from a long standing intake of roughy 3000kcal a day, to one of on average 1900kcal?

So if they were addicted to say Big Mac meals, and had one daily as a snack, and had become fairly overweight due to this habit, would they eventually get down to a healthy weight by ditching the Big Macs alone? Or would they have to keep there daily intake substantially below 2000kcal to get to a healthy weight?

It depends!

If you are severely obese, then reducing your calories to the recommended daily amount is likely to see you lose significant amounts.

As you approach a healthier weight you'll need to reduce below the daily recommendation to continue to lose.

It will be easier to focus on eating a healthier diet at first, though, rather than on reducing quantities.

And to try and. Gently increase activity levels, if they are low.

It's hard, in MN terms you could be referring to someone whose active and a size 16, or to someone sofa bound with a BMI of 42.

I was the latter, two years ago. I'm still obese, but size 16 rather than 20/22.

They say you need a deficit of 2500 calories to lose a pound so by stopping eating a Big Mac per day, the deficit calories would add up and weight would come off initially before further reducing after that.

Reducing calories so substantially would be harder and less likely to sustain so dropping the Big Mac snack would be a good place to start in my opinion.

Agree with other posters that it depends on the individual's starting point. Reducing calorie intake doesn't necessarily mean that the person would be in a deficit, it might simply mean gaining weight at a slower rate or maintaining current weight. I'd suggest either trying either suggestion for a bit and monitoring outcomes or use one of the TDEE calculators online for guide.

Good point, I hadn’t thought of that

It's impossible to say.

For some people, cutting down by that much will just lead to slower weight gain. For others, it would lead to maintenance and for the rest it will lead to weight loss - but how much weight loss depends on your activity levels, the rest of your diet etc.

I have a very active job so I could get away with eating more than I do without gaining weight - but I want to lose weight (put it on due to medication) so that means cutting down further than someone who perhaps didn't need to lose weight but has exactly the same diet and lifestyle as me.

Cutting down on calories could mean anything from losing weight to just slowing the weight gain. It depends on how many calories your burn in a day - which is some to do with exercise and also to do with how quick you burn calories at rest (varies from person. To person, with age etc)
Cutting out the Big Mac will certainly help.

It’s roughly 3500 cals to lose a pound of fat, not 2500 as stated above.

In the beginning you will likely see the number on the scale decrease more than this, from water retention changing etc.