I know your body can get used to an excercise plan and become efficient at doing the workout so you end up not burning as many calories.

Does the body do the same thing with food. If you eat basically the same food for several months does the body get used to it? Based on the calories in and calories out concept, a peice of bread has x number of calories regardless if you eat it everyday for a year. However, does the body get used to that intake and become better or more efficient at processing it so it doesn't burn as much in digesting it?

Should I only eat it for say 3 wks then jumble things up and take a break from it?

Going on the concept that the body does get more efficient at processing the food, would changing say from wheat bread to rye bread be enough or should one switch out a sandwich for something completely different?

Jumble things up so you don't get bored, but your body doesn't change how it processes over time.

It's not so much the food, it's the calorie level, for some people. There is some evidence that being at the exact same calorie level, day after day, lets your body survive more efficiently at that level (resulting in a slowing of your metabolism). Some people here "zigzag" to prevent this (eating a higher number of calories on day 1, lower day 2, etc), others just wait to see if it becomes an issue for them.

No, that doesn't happen. However, variety is still essential for good nutrition

Calorie cycling can help, mixing in one or two days a week where you slightly up your calories then a day or two where you slightly lower them definitely helps. I know for me I usually have one day a week where I go out to dinner and that ups my calories- funny thing is the day after that I usually go down in weight!

I think in the case of normal-weight and overweight individuals, there is evidence to support the theory that a body will adapt to moderate caloric restriction (I'm not talking about VLCD diets) through changing their resting metabolic rate and their output during exercise:
The abstract of the article is below:
http://www.nature.com/oby/journal/v1...y2007354a.html
Note that this is for NON-OBESE individuals. I am OVERWEIGHT, and am one of many who have experience a weight loss plateau for no outwardly apparent reasons. I suspect that the same can happen for someone who is more than overweight, but this is greatly debated.
If it DOESN'T happen, how do people who intentionally calorie restrict (eat 30% fewer calories than their maintenance caloric intake) expect to live longer? And none of them die from starvation. Their bodies adapt. In fact, there was a recent study on monkeys that showed that moderate calorie restriction does indeed increase their life expectancies --the abstract of the article is below:
http://www.ncbi.nlm.nih.gov/pubmed/12543259
And while these are indeed monkey studies, they are genetically close enough to humans to make researchers go Hmmmm...

Weight and weight management isn't necessarily linear. There are those who don't believe in weight loss plateaus or body adaptation to restricted calories. My experience kind of says otherwise, and I think there is evidence to support it.

PLEASE NOTE: I am NOT referring to those who severely calorie restrict or have eating disorders. These disorders ARE normally fatal because of the severe calorie restriction and resulting nutrient and mineral deficiencies. I am discussing the evidence that I found which relates to normal weight and overweight individuals. I personally believe that it can happen too, for more than overweight people. So don't hate!!!

I agree, this happens to me every time. I used to always wonder why then to anorexics get to a point where they could die? I think the secret is where you start.

If you start at 320... your body will wise up before you reach goal. If you start at 140 and you are anorexic you will make it to 70 or 60 no problem. This explains why some surgery people don't make it to goal.

It seems almost like there needs to be a zig zag approach to losing. Not so much daily, but you get to say 160, get stuck, go back up to 180 slowly over time to wake your metabolism up, then start back again, lose as much as you can before your body adapts, say to 140, get stuck gain again to 160 to get your body used to eating and then go back again.

Sorry, I thought the question was about repeated foods, not calorie level.

Julie, it did...I was just being thorough talking about calorie level...because if you ate the same exact foods every day for some amount of time, you'd be, by default, eating the same exact calories every day, and that's when you might get into some level of your body adjusting. But you'd also get that if you ate vastly different foods, every day, that had the exact same calorie level.