If you are in starvation mode you may gain a little bit before you see the decrease. At least thats what I read because you are suddenly eating more than you were before. After a few weeks you should start seeing a decrease. Don't get discouraged stay on plan even with some gain because you will see a decrease.
I think its more than a day or 2 of low calories. I ate a low 600-800 calories a day for 3 years and weighed 160. I now eat 1400-1500 and a few days lower and I am pushing 148. I don't think a few days or even a few weeks would put you into that mode.
Copy and paste from Mel.
BTW ... if you put 'starvation mode into a search by thread title, you will find lost of interesting opinions.
I think the term starvation mode gets used way too often here also. When I was losing the biggest chunk of my weight, I doubt that regularly I ate over 1000 calories a day, and I was exercising a lot. I was hungry, but getting the fat off was the most important thing in the world to me. It came off- no plateaus, no cheating. Those 1000 calories were extremely high in nutritional value, though, and I was doing (and continue to do) a lot of heavy weight training to ensure that I lost fat and not muscle.
Back in the early 80's I was on a commercial weightloss clinic diet where I wasn't supposed to go over 700 calories per day. I was a distance runner and racquetball player (and in retrospect, NOT fat!) and I'm sure I initially was burning more that 700 calories through daily activity, let alone my RMR. I think I did enter starvation mode on that diet- after a few weeks I felt horrible, stopped losing weight (my goal was 110 and I got stuck at 113 no matter how little I ate or how far I ran), became spacey and ineffective at work. The "counselor" couldn't figure out why I wasn't losing the last 3 pounds and kept accusing me of cheating. That diet ended when I discovered I was pregnant, which considering my health seems like a miracle. I gained 65 pounds with that pregnancy, probably due to being told to STOP DIETING. Wow, after living on 700 calories for several months, mind and body overreacted!
Starvation mode certainly exists- you can read about the Minnesota Starvation Study conducted on conscientious objectors during WWII. But these men were put on very low calorie and nutrient diets, way below the 1600 calorie level that some of our posters worry about.
When I see menus posted and a lot of the replies are "I don't think you are eating enough" I usually refrain from posting because IMO they are usually eating more than enough, but not enough healthy food. Sugar free puddings, 100 calorie snack packs, most breakfast cereals, most breads, pasta, concoctions with sugar-free coolwhip...these are empty calories. Get rid of them, add some real food, add a lot of fresh vegetables and lean proteins, and you'll lose weight.
Most competitive bodybuilders do NOT drastically cut their intake before comptetition, but monitor their nutrient ratios extremely carefully, and eat only nutient dense foods. It takes a lot of complex carbs and lean protein to maintain muscle, and no bodybuilder is willing to sacrifice muscle. They clean up their diet- chicken, lean fish, egg whites, brown rice, oatmeal, sweet potatoes, and lots of green vegies. Strictly monitored selected fats. No sauces, sugars, alcohol, dairy (it tends to hold water in the skin, "softening" the look), and for women, LOTS of cardio. But lots of food. One of my friends is preparing for a comp on October 1. She is 5'3" and weighs about 120 now and will probably weigh about 114 on comp day with a bf% 8-9%. A typical meal for her is 7 oz of plain chicken breast, 1/2 cup of brown rice, and a cup of broccoli. SIX times a day! Two to three days before competition, most bodybuilders jiggle carbs and water, but that is strictly to achieve a "show look", not for fat loss. If the fat isn't gone by then, it's too late.
This is an article that I copied and pasted from Weight Watchers:
The idea that "not eating enough" causes the body to stop losing weight because it goes into "starvation mode" is a popular myth among dieters.
Metabolism Slows During Calorie Restriction
Restricting calories during weight loss lowers metabolism1 because the body becomes more efficient, requiring fewer calories to perform the necessary daily functions for survival. Consequently, this can slow (but not stop) the anticipated rate of weight loss.
For example, if an individual needs 2,000 calories per day to maintain weight, reducing intake to 1,500 calories, assuming exercise stays the same, should provide a 1 pound per week weight loss (Note: 1 pound of weight is equivalent to about 3,500 calories). Furthermore, reducing to 1,000 calories should result in a weight-loss of 2 pounds per week and going down to 500 calories a day should result in a weight loss of 3 pounds per week. However, if an individual actually reduces their intake to 500 calories, the weight loss would not likely be a steady 3 pounds per week because of the reduced metabolic rate. It would likely be around 2 ¼ to 2 ½ pounds. This "lower than expected" rate of weight loss is a lot different than "no" weight loss as the "starvation mode" notion proposes.
It is unclear as to whether the relationship between reduced caloric intake and a lower metabolism follows a straight path or becomes more pronounced the greater the caloric reduction. Some studies have found no significant reduction in metabolism until the caloric restriction is quite large (e.g. 800 calories or less per day).2 Others suggest a linear relationship with small reductions in metabolism accompanying small reductions in caloric restriction, with the gap increasing as the caloric deficit is enlarged.
While there is no biologic evidence to support the "starvation mode" myth, there may be behavioral reasons why weight loss stops when calories are severely reduced. Over-restriction of calorie intake, known as high dietary restraint is linked to periods of overeating, hindering successful weight loss.3 (For more information on dietary restraint, read the Science Center article, The Skill of Flexible Restraint).
Metabolism after Weight Loss
The good news is that after the weight-loss goal is achieved and weight has stabilized, it does not appear that the dip in metabolism is permanent. Several rigorous studies done at the University of Alabama in Birmingham showed that metabolism goes back to expected levels with sustained weight loss,4 discounting the theory that a lowered metabolism helps to explain the common phenomenon of weight regain following weight loss.