I am a 44 yo man currently doing a medically-supervised very low calorie diet, where I am limiting daily food intake to a maximum of 800 calories per day, consisting almost exclusively of meat, eggs, and non-starchy vegetables. A tiny bit of almonds and cheese at the end of the day if I am under budget.

My doctor has me taking a multivitamin, a medication to prevent gallstones, and occasionally does an ECG and blood test to check my heart, mineral levels, etc.

At the same time I started the diet, I started a walking program and am averaging about 18,000 steps per day. This was a huge change from my very sedentary activity levels before this program. As a result, I am losing quite a bit of weight fairly quickly.

The plan was for the very low calorie phase of this program to go for 12 weeks, and after that I'll step-wise increase my daily caloric intake to 1000 calories per day for a period of time, and then 1200 calories per day for a period of time after that. However, because I've lost 40 lbs in the first 6 weeks and am approaching BMI and fat % thresholds we thought would take longer to reach, I'm wondering if I should start to increase my calories now, which my doctor said might be a good idea, although she doesn't have strong feelings about it either way.

I am not super hungry with the current limits. One of my concerns is that if I increase my calories, I might get more hungry. I read that low appetite is one of the body's adaptive responses to very low calorie intake. If I increase to 1000 calories per day, will it be a lot harder for me to stay under the limit? I still have a lot of weight to lose. I started at 258 lbs, currently weight 218 lbs (height 5’ 11”) and want to get to 170 lbs or lower.

I've attached a table and chart summarizing my weight loss journey so far:

The jury is out for me on how much doctors actually know about nutrition. 800 calories, medically supervised or not, seems dangerously low. At 5’9” and current weight of 218, I wouldn’t quibble over upping to 1000 or even 1200 calories per day. I would recommend 2000 calories per day on low carb .. meat, eggs, veggies and minimal nuts and cheese .. and you will still see the weight fly off your bones!

Keep up your walking and stay true to low carb (no bread, pasta, rice, cereal) and you are closer to goal than you realize. Weight flies off for men b/c your muscle groups are larger (thighs especially).

Be happy and keep going

Thanks for your comments! I am going to go ahead and increase to 1000 calories per day and see what happens.

I think 800 per day is dangerous. I would suggest increasing to at least 1500 per day, but most importantly make sure it's a healthy and balanced diet. If you're eating healthy then you'll feel full before you overeat.

In addition to walking, I would also suggest doing some weightlifting 2 or 3 times a week. If you have more muscle, you'll burn calories faster.

Thanks for your comments. I am doing some weight lifting 3-4 days per week.

I did 6 months last year on about 850 cal per day - basically kept going until i'd reached my goal, then increased after that to stay at maintenance. But then I am a short-arse female, and I wasn't exercising particularly. I feel super-fantastic now having got to my target weight and stayed there for 6 months!!
If you've changed to 1000 that's fine. You probably need it with the exercise you're doing. If you're eating all the right things, which it sounds like you are, and not getting hungry, and you're feeling well, then i'd say keep going with whatever you're doing til you've reached your target. You're your own experiment really, but the 'get it done' method worked for me.

Thanks, that is very helpful. When you increased your calories for maintenance, did your appetite go up a lot?

Not really. I guess my stomach was smallish by then, so smaller amounts still satisfied. I finished the main losing stage around july last year and was happy to stay on the 'new' diet of heaps of veggies and a bit of protein, with more weekend indulgencies thrown in for the extra calories (glasses of wine, meals out etc) for the rest of the year.
This year i'm feeling a bit more hungry, but i'm doing heaps more exercise, so really i'm still learning about what I need to do to stay where I am.