DEAR DR. BLONZ: This may seem like an odd question for someone who writes about nutrition, but how long can a body go without food? A close friend recently experienced a loss, which has caused her to suffer a hard emotional blow. She says that she has no appetite. She hasn’t been able to eat anything; when she tries, it results in nausea and her body’s rejection of the food.
As would be expected, she has lost a lot of weight lately, and doesn’t look healthy to me. -- F.S. San Jose, California
DEAR F.S.: My sincere sympathy to your friend, and any affected by the loss. Grief can affect the body in many ways, and while a loss of appetite can be one of them, overeating, ironically, can be another. For more on the body’s reaction to grief, visit b.link/ncbi58.
Addressing your question: Our body is designed to avoid waste, so we shift gears to handle food whenever it’s consumed. But if nutrients are not provided for an extended period, a sophisticated series of adaptations takes place to pare down the unnecessary use of energy and loss of essential resources. While we may be conscious of why we are no longer eating, the systems in our body are not in that loop.
One adaptation is a scaling-back of the metabolic efforts involved with digestion, which might explain that queasiness or nausea your friend experiences when food is reintroduced. The discomfort tends to pass, but reintroducing food in this scenario should be done gradually, relying on plant foods such as juices, soups, fruits and cooked vegetables.
A lack of food also causes a slowing of the metabolic rate, which brings about a lowering of body temperature. There will be less circulation near the skin surface, which is one of the reasons why people who go without food are easily chilled and may have a sallow look about them.
Friends and family serve as an invaluable source of support, but an inability to eat lasting for days suggests some professional assistance may be needed. In the meantime, given that the body requires more water than any other nutrient, encourage your friend to consume fluids -- even something like a sports drink, which provides not only fluids, but also electrolytes and calories. To emphasize this important point: We can last only a few days without water.
The human body can survive for many weeks without food, but much depends on one’s state of health and the amount of excess energy (i.e., body fat) at the start. I hope that your friend finds the strength to work through her grief, and is spared any testing of the limits of her endurance.
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