4 days Ago
Listen to Story Indian-origin astronaut Sunita Williams's recent update from the International Space Station in which she appeared to show significant weight loss was dismissed by Nasa, saying that "all [astronauts] are in good health." In a video, released by Nasa, she said that she measures the same body weight when she started the mission. "Things shift around quite a bit.
You probably heard of a fluid shift in which folks in space, their heads look a bit bigger because the fluid evens out along the body," said Williams . She added that she has been lifting weights and using the treadmill to maintain her weight and muscle mass. Speculation around Williams's health highlights the complexities of calorie requirements in space.
While astronauts generally require 2,500 to 3,800 calories daily depending on their workload, factors like microgravity-induced muscle and bone loss, changes in metabolism, and rigorous exercise routines can impact their weight. Caloric needs may also fluctuate based on mission demands, stressing the need for adaptable dietary strategies to maintain astronaut health and performance. During long-duration space missions, diet plays an important role in maintaining physical and mental well-being.
According to the European Space Agency , astronauts have to exercise for at least two hours a day, six days a week to avoid quick muscle loss and bone loss in space. Since they need higher calories than on Earth, two-thirds of this calorie intake comes from the basic food supply that is preselected and prepared by Nasa for the entire space mission. The International Space Station menu provides around 50% of calories as carbohydrate, 17% as protein, and 31% as fat.
A study in the Journal of Bone and Mineral Research that used heavy resistive exercise as a countermeasure to bone loss showed that adequate energy, protein, and vitamin D supply are mandatory to maintain bone mineral density after 6 months of space flight. A 2023 Nasa study revealed that for every month in space, astronauts' weight-bearing bones become roughly 1% less dense if they don’t take precautions to counter this loss. Sunita Williams and her colleague Barry 'Butch' Wilmore are set to return to Earth on SpaceX's Crew-9 Dragon capsule not before February 2025.
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