On Nutrition: Sorry, Eating a Whole Bag of Crisps Still Not a Good Idea | Lifestyles
Dear Dr Blonz: I wonder if you could comment on a family discussion. My stepdad often eats an entire bag of chips in one sitting – a 10 ounce bag, not an individual 1 ounce bag. He says his body can only absorb some of the calories it eats at a time and the rest will just pass through. This way, he claims that he will actually take in fewer calories by eating the whole bag at once than if he ate only one serving each day until he is gone. Is it true? – KB, by e-mail
Dear KB: There is some logic to your stepfather’s position: namely, that under certain circumstances there may be inefficiencies in caloric absorption when the body is facing unusual food overload. The backstory, however, can help complete the picture.
The human body is geared towards efficiency, avoiding as much as possible any waste of calories and other resources. Muscles, for example, need energy (calories) even at rest. (Think of the analogy of the gas mileage of an idling eight-cylinder car versus a four-cylinder car.) Working muscles adapt to our activity routines, increasing their mass to respond to the requirements of the usual load. The reverse is also true: Muscles shrink when decreased activity becomes the new normal.
Similar adjustments occur with digestion – system-wide adaptations to what, when, and how much we eat on a regular basis. This helps explain why we tend to be hungry at our regular meals, and why we might be at greater risk for indigestion when we eat at unusual times, such as after crossing multiple time zones. It also explains why sudden and drastic changes in the foods we eat may not “be felt easily”, even if the change is towards healthier dishes.