Eating Out on a Diet Without Wrecking Your Week

Why your guess is usually too low

In a 2013 study in the BMJ, Block and colleagues asked 1,877 adults leaving fast-food restaurants in New England how many calories they had just bought. Their meals averaged 836 calories, and they underestimated by about 175 calories on average. Nearly a quarter were out by 500 calories or more, and the bigger the meal, the bigger the miss. Diners at Subway underestimated their meals by more, relative to what they had bought, than diners at McDonald's. The authors suggested this may be a "health halo": food that sounds healthy gets underestimated.

Printed menu numbers are a better guide than your eye, but not perfect. In a 2011 study in JAMA, Urban and colleagues measured 269 foods from 42 restaurants. On average the stated calories were accurate, but 19% of foods had at least 100 calories more than stated, and the lower-calorie options were the ones most likely to be understated.

So the "light" option is not always as light as it says, and hidden extras such as oil, butter and sauces are easy to miss.

Eating out on a diet: plan the week, not the meal

Fat loss is decided over weeks, not one evening. If you are eating about 500 calories a day below maintenance, that is a weekly deficit of about 3,500. A meal out that comes in 700 or 800 calories above your usual dinner uses up part of that week's deficit. It does not erase it.

Option 1: make room for it. Trim about 100 to 150 calories a day, mostly from carbohydrate and fat, on the other six days of the week. That adds up to 600 to 900 calories. Keep protein where it is. It is the same idea as setting money aside for a night out.

Option 2: accept a slower week. If the meal is a one-off, simply eat to your normal targets the rest of the week and accept slightly slower progress. That is a perfectly good choice.

What not to do:

• Do not skip food all day to "save" calories. You arrive starving, eat the bread basket and order more.
• Do not let one meal become a lost weekend. The real cost of eating out is usually the "may as well" eating that follows it.
• Do not punish yourself the next day with fasting or extra cardio. Go straight back to your normal plan.

If you do not know your targets yet, the free calorie and macro calculator gives you a starting point.

What to order

No food is banned. These are simply the choices that make it easier to stay close to your numbers:

Usually easier	Usually adds up fast
Grilled, roasted or steamed meat, fish or tofu	Fried, battered or "crispy" dishes
Tomato-based sauces	Cream, cheese and butter sauces
Dressing or sauce on the side	Salads already dressed
Vegetables, salad or rice as a side	Chips plus bread plus a starter
Sharing a dessert, or having coffee	A full dessert each, every time

A few habits that help:

• Build the meal around protein. It fills you up and keeps you on track for your daily target. How much protein you need explains why it matters on a diet.
• Look at the menu in advance. Deciding at home, when you are not hungry, is easier than deciding at the table.
• Ask. "Can I have the sauce on the side?" or "Can I swap the chips for salad?" are normal requests.
• Pick your extras. Bread, a starter, drinks and dessert all add up. Choose the one or two you actually want.
• Stop when you are full. Restaurant portions are not set to your targets. Leaving some, or taking it home, is fine.

How to log a restaurant meal

Logging it, even roughly, beats leaving it out.

1. Use the menu figure if there is one. In England, food businesses with 250 or more employees have had to show calories on menus since April 2022. In the US, chains with 20 or more locations have had to since May 2018, and must give fuller nutrition information, including protein, if you ask.
2. No figure? Find a close match from a chain restaurant's published menu or your tracking app, and pick a realistic portion.
3. Add a margin for cooking oil, butter and sauces, especially with a big meal, since bigger meals were underestimated the most.
4. Log drinks too. Alcohol is easy to forget and adds up quickly: see alcohol and fat loss for the numbers.

If logging restaurant meals makes you anxious, or you have a history of disordered eating, there is no need to track every calorie. Speak to your GP if food and eating are taking over your thoughts.

The morning after: why the scale jumps

Expect the scale to be up the next day. Restaurant food tends to be salty and high in carbohydrate, and both make your body hold extra water for a day or two. That is water, not a day's worth of fat.

Do not react to one weigh-in. Go back to your normal eating, and judge progress on your weekly average. How to read the scale explains the daily swings.

When eating out is the real problem

One meal out a week rarely stalls fat loss. Eating out most days can. In a study of 12,528 US adults (Nguyen and Powell, 2014, Public Health Nutrition), eating at a fast-food or full-service restaurant was linked to about 200 more calories that day in total. Spread across several days a week, that can wipe out much of a moderate deficit.

If you eat out often for work or family, make your usual order a habit: a few dishes at your regular places that you know fit your targets. You then only have to think hard about the occasional special meal.

How coaching helps

Nobody can make a three-course dinner calorie-free, but you can plan for it. With one-to-one coaching from CoachAk, your calorie and macro targets live in the app and you log your weight every day. Your weekly check-in takes about three minutes and covers your weight, training and nutrition adherence, steps, sleep, energy, hunger and stress. Your coach replies with written feedback and adjusts your plan when needed. Before a work dinner, a wedding or a holiday, you can message your coach directly, with photos or voice notes, and plan around it together.

If you want to lose fat without giving up eating out, apply for coaching.