What is the most deficit you can have before your body just shuts down and doesn't lose weight? The reason why I ask is I just noticed on my fitday that my avg deficit is around 1000 calories with little activity. If I start exercising again and burning more calories per day that would bring my deficit to even more. I'm not losing now, so I'm afraid I still won't lose if my deficit gets bigger. So should I eat more to compensate or wait and see if my body needed more exercise? I don't want to make it harder to lose weight than it has to be.

Currently fitday says I burn an average of 2360 calories a day. I've been eating an average of 1350 calories a day. I've been doing some activity, but really it's not as much as it should be. Should I be eating more to compensate for the 200-300 calories I'll be burning with more exercise?

Or am I just over thinking this whole thing?

Never happens.

The real question is how strict a diet you can stick too, and whether or not you are losing too much lean bodymass on an ultra-restrictive diet. Shooting for a loss of 1-2#/week seems like a pretty safe bet for most of us.

is what shes describing though considered what you would do for a 1-2lb loss in a week?

Yes, a 1,000 Cal/day deficit would be about right. I am aiming for 2,000 Cal/day myself, but I am probaly twice as big as your average forum member.

The main thing is to count accurately, and make sure you are running a deficit. When I stop counting I slide right into maintainance even though I think I am dieting.

I totally disagree. If you cut down to 500 - 800 calories a day, your weight loss is going to stall out. And you can make yourself seriously ill. We had a guy at our office who did that to lose weight and ended up having to take an 8 month leave of absence as he made himself so ill.

Any reputable doctor will tell you that it is possible to cut your calories too much as will any reputable registered dietician. Your body needs a certain amount for your heart to beat and your blood to pump and your food to digest and all that good stuff.

Check out what gastric bypass patients are eating. I know a guy who has lost more than a 100# in less than a year by following the post operative diet of a gastric bypass patient. IMHO, it is way too restrictive an approach, but he has lost more weight than I have in the same time period.

Unless you weigh something like 60# and just lie around all day in a stupor, you will lose weight on 500 cal/day. Yes, it is difficult to get all your nutrition and it is probably losing weight too fast to be really healthy, but it is not possible to halt your weight loss by eating too little.

Its probably not possible to HALT your weight loss completely, but is IS possible to severely limit your metabolism, which has both of the following effects:
1. Slows your weight loss dramatically.
2. Makes it so if you ever start eating more than that restricted amount per day, your weight will go right back up.

Our bodies are amazing adaptors to all sorts of circumstances - they slow and speed metabolism to account for how many calories you take in. That means, if you take in 500 calories a day, your body will keep adjusting and adjusting so it needs fewer and fewer calories, in addition to losing weight. That way, when you've reached your goal weight, if you start eating 1500 calories per day (which is normal to low for regular maintenance), your body has adjusted to eating 500 calories per day, and therefore has slowed your metabolism WAY down to compensate for the lack of fuel. Thus, you'll be eating a normal amount of food for maintenance, and gaining weight like crazy.

Also, because your metabolism slows, your weight loss will too. Other less restrictive weight loss plans usually feature some sort of strategy to increase metabolism...be it additional exercise (increased muscle = faster metabolism) or some other method. Speeding up your metabolism allows your body to burn more of the calories you eat, providing you with greater calorie deficits, and slowing your metabolism prevents your body from burning as many of the calories you eat as it could, and keeping your calorie deficits lower than they might have been.

You WILL lose weight at 500 a day - but it will be nearly impossible to maintain, and will slow your metabolism, causing your weight loss to eventually slow or even stall out, in addition to the more obvious problems of not being able to provide NEARLY enough nutrients for your body.

::stepping off of soapbox - college nutrition courses have stuck in my head like glue::

From St. Vincent Catholic Medical Centers:


Very low-calorie diet for obesity
A very low-calorie diet (VLCD) may be considered if you are obese and need to lose weight quickly to protect your health and if your health professional decides it is safe for you. VLCDs generally are not recommended. A VLCD is also known as a rapid weight-loss diet.

VLCDs supply from 250 to 800 calories per day. Do not start one of these diets without the help of a health professional. Diets this low in calories do not provide enough vitamins and minerals for good health unless the diet is specially prepared. A diet that does not have enough vitamins or minerals can lead to serious, potentially fatal health problems.

These diets are not recommended if you have heart problems, blood clotting problems, bleeding ulcers, liver disease, kidney disease, or cancer or if you have had a stroke. If you are older than 50, you will need frequent monitoring by your health professional to be sure you are losing fat and not muscle.

VLCDs usually last about 12 weeks. Health professional are not certain whether it is safe to use these diets for longer periods. The average weight loss in this period of time is 10 lb (4.5 kg) to 12 lb (5.4 kg).1 If exercise is made part of the weight-loss program, the average weight loss increases to about 20 lb (9.1 kg).

However, research reports that although initial weight loss is greater on a VLCD than on a low-calorie diet, in the long term about the same amount of weight is lost in both types of diets.2

People on these diets often feel tired or have constipation, nausea, or diarrhea as a side effect. However, for most people, this goes away in a few weeks.

The most common serious side effect is developing gallstones. People who are obese are more likely to develop gallstones than people who are lean, and when a person who is obese uses a very low-calorie diet, the chance that he or she will develop gallstones becomes even greater.

Following are the changes your body goes through during a VLCD:

Your metabolism slows to conserve energy because the body thinks it is starving.
To get needed carbohydrate, the body breaks down protein. This causes a loss of lean body mass such as organ and muscle tissue. It is important to preserve lean tissue, since it increases your basal metabolic rate. Losing too much lean tissue increases the percentage of fat in your body. The result is a reduced metabolism. This is one reason why it is so easy to regain weight when you lose weight quickly.
In a VLCD (or during starvation), about half the weight you lose is fat and the other half is lean tissue, such as muscle. On a more moderate diet, the loss is about 75% fat and 25% lean tissue.
Mineral and electrolyte imbalances can occur. These imbalances can be life-threatening. This is the reason these VLCDs must only be used under a health professional's supervision.
Bone mass is lost. This is more risky for women, because they diet more often than men, and they are also at higher risk for developing osteoporosis.
References
Citations
Agras WS (1998). Obesity. In DC Dale, DD Federman, eds., Scientific American Medicine, section 9, chap. 3. New York: WebMD.

American Gastroenterological Association (2002). AGA technical review on obesity. Gastroenterology, 123(3): 882–932.

Credits
Author Ellie Rodgers
Editor Geri Metzger
Associate Editor Terrina Vail
Primary Medical Reviewer Adam Husney, MD
- Family Medicine
Primary Medical Reviewer Caroline S. Rhoads, MD
- Internal Medicine
Specialist Medical Reviewer William Jody Wilkinson, MD, MS
- Weight/Fitness
Last Updated May 27, 2005

I personally was talking about eating 1000 calories less than what my body uses, not just eating 1000 calories. I agree that eating only 500 calories a day is harmful if you aren't under a doctor's supervision.

My situation is that I've been eating around 1300 calories a day. Fitday says I need 2300 calories a day. That is 1000 calorie deficit which means I should be losing 2 lbs a week. But for the last month I haven't lost anything. What I'm thinking is that maybe I need to eat more. Surely my maintanence level isn't 1300 calories when I'm 5'2" and 177 lbs.

Either way I am uping my exercise and doing calorie cycling now to see if this helps me.

You could just be in a stall, which might take some time to break. Also, are you putting in your hours sleeping into Fitday? That reduces the calories you need per day.

You could be retaining water; I go up and down a good seven pounds based on hydration. If you are accurately counting your calories, then I am sure you are losing fat, whether or not you are seeing it on the scale yet.

See what you weigh 4 weeks from today. You will probably be 6-10# lighter.

Tracking your weight and calorie totals over time will reveal your real numbers for your BMR. Fitday just gives you an educated guess.

I find Fitday to be overly optimistic when it comes to your estimated calories. Over the past 3 months, I have tracked every calorie eaten, and every calorie burned with exercise. I was surprised to discover that my daily basal calories (not including exercise) come in around 1831. I am quite a bit heavier than you, too, so it's possible that your daily amount might be even smaller.

I'm gonna jump in here with three suggestions.
#1. You could be stuck. Try just shaking things up a bit. Experiment with foods and various exercises.
#2. You could be plateau-ing. Just hang in there and stay on plan. It'll come.
#3. Fitday is a tool. One that takes some finagalling to make work effectively. Like a couple of people have said already, it's an educated guess based on averages. If you have an average intake of 1400 cals for the last month and really (really) have lost no weight ... you need to fiddle with the activity level. It is quite an ego punch for most of us, but we aren't as active as we think. My basal is only around 1200 cals and my everyday housewifely duties only use about 500. So if I don't work or exercise my usage for a day is only about 17 or 1800. Really. I kid you not. History and accurate record keeping do not lie.
So my suggestion is ... set your activity level lower and increase your defict by eating whole natural foods and getting more vigorous exercise.
If you're going to be in error, it's much nicer to undershoot and find you're losing faster than fitday says. Then we'll help you tweak it to reflect the facts.

I have used one of the math formulas out there to figure out my BMR and activity level to know how many calories my body uses. It gave me 1960 or somewhere in the 1900's.

Because of this I would need to cut back my calories to 1200 and to burn another 300 calories every day through exercise just to be able to lose 2 lbs a week.

Ok, so I've been averaging 1300 calories a day which still gives me a 600 calorie deficit so I should be theoretically losing 1 lb a week at least?

It's just all so frustrating to keep reading that it comes down to calories in vs. calories out and that theory is just not working for me. I eat really well according to my nutritionist. So I guess it just comes down to either my body is being really stubborn, or I need to up my exercise. But I don't want it to come to me working out 2-3 hours a day just to burn enough calories to even lose weight.

How was I only gaining a couple lbs a month before when I ate 2500-3500 calories a day? I guess I just need to vent this week. I went through a plateau in March. Then at the beginning of April I lost 6 lbs because of the stomach flu. Then I went into another plateau. I'm starting to think the only time I can lose weight is when I'm really sick.

I really am trying to have a positive attitude about this and focus on how far I've come. And that works for about a day. My main goal is to be healthy and in better shape. I am doing that and I'm happy. But still a part of me just wants to finally (after being overweight for 22 years) lose the weight. I did put the scale away so that isn't such a problem anymore.

I really do appreciate all the help I get from you guys. This is such a great supportive place. Actually the best group of people I've come across online. I wish you could know how much it really does mean to me to have support and help when I need it. Thanks so much!

I have lowered my activity level in Fitday and added sleep into the activities. This lowered my daily calorie usage to around 1900 which is closer to the number I'd gotten before. It's just hard to know who to trust and what is right online.

I'll be going with this number from now on and seeing if that helps. Thanks!