Astronauts' weight change?

[Pan]

Is there evidence that weightlessness in outer space tends to cause or accentuate weight change among astronauts and cosmonauts? If so, has this been significant enough for any efforts to be made to combat it?

[gus_tatory]

interesting corollary to Pan's question, imho:

light-deprivation causes people to eat more carbs (via SAD research.)

is light-deprivation an issue in space? are cosmonauts given more vitamins A and D to make up for the lack of "sunlight"?

edited to add: i mean "do astronauts eat more?", inherently because they are in space?

Edited January 13, 2004 by gus_tatory (log)

[Vickie Kloeris]

No astronauts do not eat more because they are in space. Because of the lack of exposure to sunlight, we do make Vitamin D available to the crewmembers at the request of the flight surgeons. However, most crewmembers do not use the Vitamin D we provide, since most have arranged with their flight surgeons to take a multiple vitamin that normally contains Vitamin D. Astronauts and cosmonauts do usually experience weight loss during flight. Part of it is due to fluid loss which occurs when a crewmember enters microgravity. The shift of fluids to the upper part of the body in microgravity causes the body to eliminate some water, resulting in weight loss. Also, bone loss and muscle loss occur in microgravity and these can also contribute to overall weight loss. On Shuttle flights, the weight loss is usually due to fluid loss and a failure by the crewmembers to consume enough calories to maintain body weight. On Shuttle flights, the crewmembers tend to skip a lot of meals because they work non-stop.

[CalorieLab]

Is each astronaut's meal especially designed for him or her, caloriewise? Do small women get less food than large men? How do you go about determining the caloric needs of each astronaut?--via standardized charts or is there a more direct measurement of the needs of each person?

Mark

[Vickie Kloeris]

The menus are set up for each crewmember based on their specific requests from the lists of available food items. We have the nutritional information for all the food items in a data base. After the crewmember chooses their menu, we analyze that menu and give them feedback on the nutritional content of their menu, including calories. The number of calories required for each crewmember is determined from a World Health Organization equation. The number calculated from that equation is the target number of calories used in planning the menu. The menu does not have to contain exactly that number of calories. We just want it to be within a reasonable quantity of that value. Yes, small women get less food than large men because they choose less food.

[CalorieLab]

The number of calories required for each crewmember is determined from a World Health Organization equation.

Thanks, Vickie.

I found these online--are these what you were referring to when you mentioned the WHO equations?

Male
3-9 (22.7 x body weight in kg) + 495
10-17 (17.5 x body weight in kg) + 651
18-29 (15.3 x body weight in kg) + 697
30-60 (11.6 x body weight in kg) + 879
>60 (13.5 x body weight in kg) + 487

Female

3-9 (22.7 x body weight in kg) + 499
10-17 (12.2 x body weight in kg) + 749
18-29 (14.7 x body weight in kg) + 496
30-60 ( 8.7 x body weight in kg) + 829
>60 (10.5 x body weight in kg) + 596

Mark

[Vickie Kloeris]

I don't have the exact equations handy. I would have to check with my dietitian who does that actual calculation, but they are very much like the ones you show here. It seems like the one we use also has a provision for a low, medium or high activity factor and we use the medium activity factor. Another very similar equation is the Harris-Benedict Equation which you can find on-line and will basically give you the same end value. There are several equations/methods out there for calculating caloric requirements, but they will all give you fairly similar bottom lines.