Why It's Optimal to Gain Weight on Vacation: Lessons for Daily Life

Most people gain weight because of a combination of low amount of exercise and poor portion control.

In the US, there is a wide variety of chains open nearly 24/7 where you can get, say a small hamburger, or a single bean burrito.

As you mention, outside the US, who knows what kind of food, how much, or when it will be available? (Although you can pick up a veggie burger from Euro McDonalds in many countries now)

A particular perversity that my wife and I engage in is going to "stylish" restaurants or tappas places where they provide very small dishes, but typically at prices at or above the price of a huge steak at Applebees or TGI Fridays. (Even TGI Fridays now has a "small portion" submenu though).

When I travel overseas, I walk more, skip snacks, and lose weight.

On vacations, our family of four operates in the same manner: overeating in anticipation of fewer food options on the road. During our last vacation to Disneyland, we ended up eating a lot of the free continental breakfast, a large lunch, and snacks for dinner (too stuffed for much else). Not very healthy but safer than listening to hungry, whinny kids. The result? I gained 0.5 lbs over 5 days.

That's funny. I'm just the opposite. I frequently lose a little weight on vacations, taking the same opportunities Bryan fears as opportunities to incorporate intermittent fasting, a practice which I find difficult to do at home because of the ubiquitous food.

I can’t think of too many people for whom weight gain, whether at home or on vacation, is optimal. Foregoing an opportunity to eat in order to tour Avignon in the afternoon instead of opting for dinner at a local routier provides more benefits (save money, lose weight) than costs (tummy grumble). However, if I’m ever lucky enough to visit France (or any other European country, for that matter), I intend to “eat ‘til I can’t see my feet” at every opportunity (a very satisfying, if unappealing, type of revealed preference).

I've noticed the same problem when I visit relatives. I eat nearly every meal with them and their appetites are small. If I eat lunch at a restaurant during my time there I make sure to eat quite a lot because I don't know whether my dinner at their home will be sufficient to keep me from being hungry later in the evening.

My problem with the "never eat unless I'm hungry" diet is that when I do that, I gain weight. Lots of it. A thermostat turns on the heater whenever the temperature is too cold. Now, imagine hunger as a thermostat, which sends the "hungry" signal to get one to eat when it senses "not enough food." My "hunger-stat" is very nearly in the "stuck on" position. It's even sometimes "on" when I'm objectively stuffed. If I eat "only" when hungry, I'm eating all day, and gaining insane amounts of weight. If I apply the "never eat unless I'm so hungry I'm driven to distraction" then I can keep the weight gain down, and eventually stabilize -- albeit at a much-too-high weight.

My problem, therefore, is to try to find foods that maximize hunger reduction per calorie. In recent months, by combining very careful food choice with the "never eat unless I'm so hungry I'm driven to distraction" rule, I've been able to lose about 18 pounds off my all-time high. Trouble is, I'm still more than 100 pounds overweight.

Please, don't assume everyone is the same. Some people are like you can stay at a reasonable weight. Some people are like me and have to force themselves to tolerate hunger just to stay "only" 100 pounds overweight. And one person I know is almost never hungry, and has to remind himself to eat one reasonable meal a day to avoid being underweight.

Remember, just as people have different preferences (utility functions), people also have different physical reactions to the same conditions.