I started at 6'3" 333 a little over a week ago, a BMI of 40.9. Definitely not great. A BMR calculator has my maintenance level for that height/weight at around 2700.

I started religiously journaling my meals, resolving to eat less garbage, drinking a lot more water (about 2100ml a day is what I can do comfortably).

I'm averaging roughly 1600cal per day now after doing this for about a week. Hunger was annoying, but after about day 3, that stopped being as much of an issue. I think my appetite is slowly being recalibrated. Macros for the week average 25% carbs, 48% fat, 27% protein.

Anyways. Exactly a week in, after a morning weigh-in, I got 326. 7 pounds a week seems ridiculously good from a progress standpoint, and I know there's no way in heck I can maintain that pace.

I've made no changes other than diet. I work a desk/IT job, doing a lot of late nights, and spend a lot of time sitting with nothing other than an under-desk elliptical to keep moving. I have started no special exercise program.

I'm curious how long I can expect this level of progress. I know there's no way on earth I can (or probably should!) maintain a 7 pounds per week pace. What can I reasonably expect to see a few months in the future if I stay at this diet and activity level?

  • Your BMR is what your body needs to survive and your total daily energy expenditure (TDEE) is an estimate of the calories you burn in a day. If you calculated your BMR at 2700, your TDEE might be closer to 3200. That means you're likely in a 1600 calorie deficit rather than 1000. – C. Lange Jan 24 '20 at 16:14
  • @C.Lange - I was assuming he meant TDEE there as a BMR that high is just way too unlikely. Of course that’s just me assuming, but I’m not sure it’s actually relevant to the question being asked. Understanding the difference has educational and practical value, but the question is simply about if deficits will produce weight loss. Calculators are handy, but they can be used incorrectly or be inaccurate- the effect produced from your eating habits (change in weight) is therefore a more reliable indicator when you account for things like water variance. – JustSnilloc Jan 25 '20 at 13:48
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    @JustSnilloc - absolutely. I mentioned it more so as an educational point. I'm not sure which he used either but an additional 600 calories lost per day isn't insignificant if you're tracking everything. – C. Lange Jan 25 '20 at 14:09

A true calorie deficit will ALWAYS result in weight loss, so the short answer to this question is "forever".

However, the long answer is going to be more nuanced. See, our bodies don't want us to starve to death so there are compensatory mechanisms that take place to prevent us from rapidly approaching death. These compensatory mechanisms decrease our energy expenditure by slowing down or shutting down things that are deemed less important. Of note, women will even (temporarily) lose their menstrual cycle if a deficit is too hard for too long. Generally though, things will simply slow down and you'll find that you have less energy. There is also the fact that as a person loses weight, there is less body to consume energy, and thus your energy expenditure decreases as you become smaller.

So the goal in any long term weight loss plan is to have something sustainable without causing a person to crash and burn. Ideally you want to preserve or even add lean mass, at least part of the reason for which is that lean mass is more metabolically active (it burns more calories). So what should a person do then? Maintaining a caloric deficit that results in losing 0.5-1.0% of your total weight each week is the most sustainable and if you have quite a bit of weight to lose, going up to 1.5% is fine. The first week or two of a diet will result in quite a bit of water loss and water can cause drastic changes in weight. Water isn't actually a concern, but it is something to consider when you weigh in. If you can weigh in more than once a week, you can average those weigh-ins out across a week and have a more reliable number that does a good job at cutting out water fluctuations.

Bonus - Given your statistics, you'll be at a the top end of a healthy weight when you drop below 200 lbs (199). So calculating that out results in you reaching that point in 2 years at a rate of 0.5% of your body weight each week. 1 year at a rate of 1.0% of your body weight each week. 8 months at a rate of 1.5% of your body weight each week. From a practical perspective, I would expect it to take between 1 and 2 years. Just remember that consistency will always trump intensity with these sorts of things. Try to incorporate changes gradually and you'll find them easier to stick with, because you have a lot of weight to lose, you'll be making a lot of changes so do your best to make them a part of your new lifestyle. Good luck!

  • -1 There is very little evidence that calorie restriction is effective in the long term, for the compensatory reasons you discussed. In fact, there is evidence that calorie restriction can result in a permanent reduction in calorie expenditure, even after the lost weight is inevitably regained, leaving people at their previous or higher weight, but requiring that they eat less in order to avoid more weight gain. In other words, your advice is not helpful, and is potentially harmful. – michael Jan 23 '20 at 18:15
  • @michael - Are you suggesting that a caloric deficit will not always produce weight loss? Because that's the principle behind why we need food to survive, if we don't consume enough we can't sustain the total of our mass and thus weight loss occurs. If you have some cutting edge study suggesting that humans are incapable of starving to death or that consuming less calories than you expend doesn't result in weight loss that would be an interesting read. – JustSnilloc Jan 23 '20 at 18:26
  • Also, there is certainly NOT any evidence for calorie restriction resulting in a PERMANENT reduction of calorie expenditure, but evidence for LONG TERM reductions certainly does exist. Of which most tends to come from having less body mass, the next biggest (but not necessarily long term) factor is NEAT, and the final thing which I believe you are suggesting is from the resting metabolic rate which might be hurt as much as something like 100 calories IIRC (maybe it was less) - regardless it's minimal. I can't remember which researcher was speaking on this. Maybe I'll come across it again. – JustSnilloc Jan 23 '20 at 18:56
  • Permanent reduction in expenditure due to calorie restriction: ncbi.nlm.nih.gov/pubmed/27136388 . Now it's your turn, show me the study where calorie reduction resulted in long term weight loss. Good luck with that. – michael Jan 24 '20 at 14:31
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    Here's a short commentary that researcher James Krieger hd to offer on the matter - community.myfitnesspal.com/en/discussion/10384484/… – JustSnilloc Jan 25 '20 at 0:31

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