What is the mechanism behind re-feeding syndrome?

Re-feeding syndrome occurs when someone who has been malnourished or in a state of prolonged fasting begins to eat again, particularly with a diet high in carbohydrates. The mechanism involves a rapid increase in insulin secretion in response to the consumption of carbohydrates. When carbohydrates are reintroduced, glucose levels rise, leading to significant insulin release. This insulin surge is responsible for driving electrolytes, particularly phosphate, potassium, and magnesium, into the cells.

As the body undergoes this metabolic shift, the demand for electrolytes increases due to the rapid cell proliferation and the anabolic processes that are activated. In individuals who have been in a state of starvation or malnutrition, their bodies may be depleted of these crucial electrolytes, leading to imbalances that can result in serious complications, including heart failure, respiratory failure, and neurological symptoms.

In summary, the correct answer highlights the crucial role of carbohydrate intake in the onset of re-feeding syndrome through the associated insulin response, which subsequently triggers shifts in electrolytes that can have perilous health consequences when not carefully managed after a period of nutrient deprivation.