Weigh 329 lbs eating 1,500 calories

I wouldn't stress about it. Being heavier you burn more calories because it takes more energy to move. But if your not feeling starved or overly tired etc don't stress. Just don't go into dispear if your weight loss slows, it will be just the fact you've got fitter, or are burning less due to have less to carry, or water retention for exercise. Keep up the good work every pound lost is one less you have to carry

You're probably looking at adaptive thermogenesis. A fat body has a higher metabolism than a skinny body because that's what it takes to keep a fat body moving. As you lose weight, your metabolism slows as a survival feature. A skinny body just doesn't need that much energy burn.

Furthermore, your body doesn't recognize the difference between "eating less to lose weight" and "eating less because I'm starving." You start taking in less calories and your metabolism will slow as your body fights to preserve your life and energy.

That said... it doesn't matter. It will never slow enough to prevent you from losing weight. Look at those poor souls on Biggest Loser. Those were very obese people exercising 7 or 8 hours a day and eating, in some cases, less than 800 calories a day.

They still lost major weight. And while studies show their metabolism slowed more than usual, it was by a comparatively small amount.

Don't go on an actual starvation diet, for so many reasons, and stop worrying about your metabolism. If you do this right and hit a plateau at some point, you can go on a diet break, spend a couple weeks eating at maintenance, and your metabolism will pop right back up again (because you won't be "starving.")

1) Did your doctor tell you that you needed to lose 19.4 lb. by July 7th? If not, then there's no reason why you need to pursue an aggressive deficit in order to meet this arbitrary goal. Nothing bad is going to happen to you if you don't lose that amount in that time, and nothing good other than a temporary sense of satisfaction, and having lost 19.4 lb., will happen if you do. But what if you lose, say, 17 pounds in that time frame? Will you feel sad that you didn't meet your goal, even though you lost 17 pounds? And if you have to make yourself miserable to meet this goal, will you want to continue your weight loss long term? I would strongly recommend not putting arbitrary deadlines on your weight loss. Consistently stay in a reasonable deficit and you will lose weight.

2) Nutrition is good for other health and fitness goals, and it is important to get proper nutrition, but your macros are not directly relevant to weight loss. Weight loss happens in a calorie deficit. For the purposes of weight loss, it doesn't matter what macros you get those calories from.

3) People can feel full while undereating from a variety of things, from filling up on lots of very low calorie/high volume food, to drinking too much water and feeling full because of that.

5) Is 19.4 lb. all the weight you want to lose? If so, then after you lose 19.4 lb, you should gradually add calories back until you're eating at maintenance. But if you want to lose more weight than that, it does not make sense that you are temporarily pursuing an aggressive deficit until you reach an arbitrary goal. Overly aggressive deficits are more likely to result in fatigue, psychological burnout, and health problems if you continue them long enough. Eat at a reasonable deficit now, not 19.4 lb. from now.

6) Why would you wait and see if you have health problems, instead of doing what you can to prevent them in the first place?

At your size for that amount of time, I doubt that 2.6 lbs/week is too aggressive. It likely is long-term, but it appears you have a handle on that concept already. (i.e. don't do that long-term even if it becomes intoxicating to watch the numbers fall quickly). For the 7 weeks between now and then, you're probably fine.

Shifting to the long-term view, preserving muscle and maintaining appropriate energy for activities is best achieved at a slower rate, which may test your patience. But it is well worth it. Play the long game. You'll be happy you did!

Given your starting weight, a loss of up to 1 percent of your bodyweight per week should be ok. Definitely be sure your protein stays on the high side to help prevent too much muscle loss. If you start losing too quickly, I’d recommend readjusting your plan.

Side note - 1500 calories still sounds low. I lose at 1500-1600 daily and am 140 lbs at 5’1” tall with my activity level.

Most of the evidence I have seen suggests that a loss of 0.25 to 0.75% of bodyweight per week would facilitate a minimal loss of lean mass. And there is lots of agreement to extending to 1% for the same. There is even quite a bit of agreement extending that to up to 1.25 or 1.5% of bodyweight per week.

And when your fat to lean mass ratio is where it is currently, you are probably quite safe losing at both more than 2lbs a week AND at a faster rate approaching that 1.5%

But before we all get too sure of ourselves... the rates of bodyweight per week only apply in the context of successfully applying the deficit.

And the larger the deficit and leaner the person the less likely the success of the application!

THAT SAID.

Your "hunger" right now while you're at a deficit says nothing about your hunger long term or what will happen when you experience rebound hunger when you eventually exit your deficit. And whether that rebound is more likely and more intense if you apply too large of a deficit for too long.

CAN THE DIET BETS. You will probably win this one because you're in an ideal position to do so. However, long term, your motivation better be your own.

Fun and games are fun but if you don't discover your inner reasons for losing the weight and maintaining the weight loss, the money motive is not going to help you manage.

Also weight loss does not, long term, happen on a time table. Just because you applied your deficit today does not mean it will be reflected on the scale tomorrow. And the opposite holds true too.

Right now your losses are working like clockwork for you because you're in a position of being able to apply an excessive deficit. You won't be able to do so for the full length of your weight loss. And if you do try to apply an excessive deficit for the full length of your weight loss, the likelihood of a rebound, in my opinion, increases.

You have a long period of loss in front of you, If you do it at a reasonable pace. We are talking a couple of years, not a couple of months. If you incorporate the occasional refeeds. If you incorporate diet breaks when you need them. If you manage the weight loss and keep things manageable you may get to the end of it knowing enough about yourself and having enough tools in your tool-belt to successfully defend your weight loss.

If you decide to go hell on wheels instead, I hope that you have a competent team around you who will offer the nutritional support, and the counselling and insights you will not have the time to self discover.

You need time to develop new habits and a new relationships with food, general activity, and even exercise. And you need the time for these habits to become quite embedded before you're done with your weight loss phase/honeymoon of feeling good while losing weight.

Spend your time trying to discover a variety of foods that are filling and which you enjoy eating and which will work for you long term. Spend your time trying to change your life around so that you have more options for daily activity and a layered defence plan for when things go sideways--because they always do.

Health, injuries, family, job, all these things tend to interfere with our plans and need to be accommodated to first of all succeed with and then defend the weight loss.

Last thought for you.

Do you see yourself eating @1500 Cal a day for the remaining years of your life? Are you just on a diet, or should you also be figuring out and practicing how you're going to function in the coming years?