DEAR DR. BLONZ: I wonder if you could comment on a family discussion. My father-in-law often eats an entire bag of potato chips at one sitting -- a 10-ounce bag, not an individual 1-ounce bag. He says that his body can only absorb so many of the calories that he eats at once, and that the rest will just pass on through. In this way, he claims he will actually absorb fewer calories by eating the whole bag at once than if he ate just a portion every day until it was gone. Is this true? -- K.B., via email
DEAR K.B.: There is some logic to your father-in-law's position: namely, that in some circumstances, there can be inefficiencies in caloric absorption when the body is dealing with an uncharacteristic dietary overload. The backstory, however, can help complete the picture.
The human body is oriented for efficiency, avoiding any waste of calories and other resources whenever possible. Muscles, for example, require energy (calories) even while at rest. (Think of the analogy of gas consumption by an eight-cylinder car at idle versus a four-cylinder car.) Working muscles adapt to our activity routines, increasing their mass to meet the demands of habitual load. The converse is also true: Muscles shrink when decreased activity becomes the new norm.
Similar adjustments occur with digestion -- system-wide adaptations to what, when and how much we regularly eat. This helps explain why we tend to get hungry at our typical mealtimes and why we might be at greater risk for indigestion when eating at unusual times, such as after traveling through several time zones. This also explains why abrupt, radical shifts in the foods we eat might not "go down easy," even if the change is toward more healthful fare.
Does the above suggest that having a 10-ounce bag of chips -- the equivalent of 10 1-ounce servings -- at one sitting might be an acceptable strategy? Hardly. Downing that full bag will result in increased blood levels of the chips' food components -- approximately 90 grams of fat, 160 grams of carbohydrate and 1,500 mg of sodium. All of that will be waiting in the queue for absorption, and it is complemented by few, if any, healthful assets.
Fat, carbs and sodium are not the snack-food elements you want to accentuate, even if absorption isn't happening with 100% efficiency. What fails to be absorbed ends up traveling the rest of the way through the intestines, bringing nutrients to areas where they're not often seen. This can result in indigestion, gas and other negative effects. And if the bag of chips is consumed within a couple of hours of another meal, the digestive and absorption machinery will already be up and running -- robbing the assumption of caloric wastage of its heft.
A sizable load of fat, carbohydrates and sodium, from a processed food with few healthful assets, increases elements associated with many chronic diseases. So even if you feel you can defend the action using a caloric-inefficiency rationale, health logic argues that you are not doing yourself any favors.
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.