Can you get away with eating too much on vacation?
Summer’s around the corner and with it vacations, trips, fun stuff. Sticking to the best food choices, however, can be challenging when you're away from your routine.
Since I don’t subscribe to the notion that we should stick to a perfect diet all days of the year I want to believe that our body is forgiving, adaptable, and doesn’t expect us to be on our best behavior more than, let’s say, 80-90 percent of the time. To fully experience another culture, another country, an excellent restaurant I’d like to put aside food worries.
What are the consequences of letting go every once in a while?
The good – and the bad – news
A new study offers both reassurance and forewarning.
Researchers overfed a small group of young, healthy, non-obese men in two experimental settings, one resembling a holiday or a vacation – 5 days of indulgence – and another approximating chronic overeating – about a month of immoderation.
The study, published in the American Journal of Physiology - Endocrinology and Metabolism specifically chose to test the sort of over-consumption typical of a Western diet. The volunteers ate their normal diet, and on top of it had 1000 extra calories derived from high-calorie snacks such as chocolate, potato chips and meal replacement drinks. The researchers, led by Dale Morrison, measured many metabolic parameters, such as blood sugar and insulin, as well as C-peptide, an amino acid that is released in response to increased production of insulin.
And the results: 5 days of overfeeding had little effect on body weight and body fat, but 28 days changed body mass and fat mass: after 28 days participants gained on average 3.5 pounds of weight, of them, almost 3 pounds of fat. This is no wonder: 28 days of 1000 extra calories are 28,000 additional calories, much greater than the extra 5000 calories consumed after just 5 days.
What’s interesting is that after-meal blood glucose levels spiked only when participants overfed for 28 days. Insulin response was also increased only in the chronic overfeeding condition. These changes in insulin production and insulin clearance are suggestive of the emergence of insulin resistance – the body loosing its sensitivity to insulin.
This study is small, but may suggest that at least in healthy, young people, short-term overeating is buffered; the body regulates and shifts the excess energy so that glucose and insulin are kept quite stable, and even weight doesn’t change much.
On the other hand, oversupply that lingers for about a month can take its toll and may have metabolic consequences.
Obviously, the more you repeat a damaging behavior the more of the exposure you accumulate, but beyond that, the more you repeat a behavior the greater the chances of habit formation.
Holiday weight gain
People often return from vacations saying they gained a lot of weight, but despite the widespread impression that vacations contribute greatly to waist size there isn’t a ton of research on the subject
A recent review in the journal Obesity included six studies in adults, and five of them showed significant weight gain over the winter holiday season. One of the studies observed 195 adults over 6 weeks, from late November to mid-January, and showed that they gained an average of 0.8 pounds – weight they kept a year after. In four other studies holiday-season weight gain was even greater and ranged from 1.2 to 2 pounds!
As to summer trips, a study in Physiology and Behavior followed 122 people over their 1-3 week vacations, and found that they gained on average 0.7 pounds. The extra weight persisted 6 weeks after the vacation was over.
Just don’t go crazy
If you’re looking for permission to overindulge sometimes you may find reassurance in the findings above. I’m biased towards that approach since I love food and food experiences, and believe in moderation. Even healthy eating can use some moderation.
This certainly isn’t permission to go crazy, nor does it suggest that anything goes. Short periods of indulgence might be worth their modest price; longer periods however may affect long-term weight gain, metabolic health and can form unhealthy habits.
So, if you wish to indulge make it short and remember to get back into your lane: it’s too common to think that after you overate once you might as well keep going. No, you didn’t blow it, tomorrow is another day.
And a few tips for not going overboard.
Splurge where it matters to you, when the food’s really worth it, be active, that helps with pretty much every aspect of wellbeing and health, and watch what you drink: sugary drinks not only add to your caloric burden, they also don’t register the way solids do, and may increase appetite and food intake.