Gaining what - fat, muscle, or water?

Question
Dear Dr. Z --

In the past few months I have lost about 15 lbs due to decreased calories, improved nutrition choices and increasing my physical exercise.  I weigh myself on the same scale once a week to stay motivated and track my progress.

My question is how fast does the body manufacture fat and muscle?  For example, I weighed myself yesterday morning and just for fun again this morning (after a big dinner out and a few drinks with friends) and today I weighed two pounds more.  I'm sure weight fluctuates frequently like blood pressure and pulse due to various factors, but is all that food and drink still inside or did my body already turn it to fat?

Thank you!

Answer
Dear Jill,

To gain 1 pound of pure fat, you must overconsume 3500 Calories. To gain 1 pound of water, you can just eat a little bit more salty food.

If it's a matter of days, your weight gain is completely water gain. So, in certain sense, your dinner indeed stays inside, but rather the water-retaining part of it since the food bulk travels out within 8 hours.

Muscle gain is usually half a pound a week and is possible if you eat enough of protein-rich food AND do strength exercises.

In case you are curious, you can track your true body composition changes instead of just using the scales, here:

http://dietandbody.com/article1113.html

Good luck,

= TZ

1. Prev:Hunger
2. Next:OCD and diet