Eating out and takeaway: logging the meals you did not cook

Nobody struggles to log a chicken breast they weighed themselves. The log goes quiet on Friday night, at the restaurant, over a plate that arrived without a label and a menu that said nothing about how much butter went into it. That is exactly when the day gets interesting, and exactly when most people stop writing it down.

Which is a shame, because meals you did not cook are where the calories hide. Not because restaurants are villains, but because a kitchen that is paid to make food taste good uses more fat, more salt and bigger portions than you would at home, and none of that is visible from your seat.

How wrong the guess usually is

When researchers ask people to estimate the calories in a restaurant meal they have just ordered and then measure it, the guesses come in low, and they come in lowest for the biggest meals. A study of frequently ordered dishes at independent restaurants found the average main course carried well over a thousand calories - before the drink, the bread and the dessert. That is not a treat. For a lot of people that is most of the day on one plate, and the plate looked perfectly ordinary.

The mechanism is simple. At home you see the oil go into the pan. Out, you see the finished dish, and finished dishes do not look like their fat content. A "grilled" salmon can arrive with a butter sauce that outweighs the fish, calorie for calorie. A salad with the dressing already on it can be the heaviest thing on the menu. The eye is a decent judge of portion size and a terrible judge of density.

Roughly right beats an empty day

The first instinct is to give up on precision, and the first instinct is right, but people take it one step too far and give up on the entry. An estimate that is off by a couple of hundred calories is a small error in a week. A skipped meal is not an error - it is a hole, and a hole in a log pulls the week's average down to a number that is simply not true. If you are cutting and your weight is not moving, the missing Friday is the first place to look.

So the rule is: something goes in, every time. A photo of the plate. The name of the dish and a rough size. The restaurant's own menu numbers, if the chain publishes them. Any of those beats nothing, and all of them get better with practice.

A few things that make the guess better

• Guess the fat, not just the food. The protein and the starch on a restaurant plate are usually what they look like. The fat is what you cannot see. If it tastes richer than you would make it, it probably was, and rounding up a little on those dishes corrects for the bias in the right direction.
• Take the photo before you start. Half a plate of noodles is much harder to estimate than a whole one, and your memory of what a whole one looked like is unreliable by the second glass of wine.
• Log the drinks. Two beers or a couple of glasses of wine are a few hundred calories that never appear on a plate, and they are the part people most reliably forget.
• Takeaway is easier than it looks. Delivery boxes are standard portions, and a lot of what arrives in them has a barcode or a menu entry somewhere. A pizza box is a known quantity in a way a friend's casserole never will be.
• Do not try to win back the meal. A big dinner out is a big dinner out. Skipping breakfast to atone for it usually ends in a bigger lunch. Log it, let the week absorb it, and move on.

What eating out is actually for

None of this means the answer is to eat out less. It means the answer is to stop treating a meal someone else cooked as a meal that does not count. Two or three of those a week, logged roughly and honestly, are entirely compatible with any reasonable goal. The same meals, unlogged, are how a careful week turns into a mystery on the scale. The food was never the problem. The blank line was.

Sources

• Urban LE et al., "Energy contents of frequently ordered restaurant meals and comparison with human energy requirements and US Department of Agriculture database information", Journal of the Academy of Nutrition and Dietetics, 2016. pubmed.ncbi.nlm.nih.gov/26803805
• Block JP et al., "Consumers' estimation of calorie content at fast food restaurants: cross sectional observational study", BMJ, 2013. pubmed.ncbi.nlm.nih.gov/23704170