How to count calories without weighing food

Is counting without a scale accurate enough?

For most goals, yes, as long as you're consistent. A 2011 systematic review found that keeping track of what you eat was consistently linked to weight loss, although the studies behind it had weaknesses. In a 2014 study of 220 women, frequent logging predicted less weight regain only when people logged on more than 3 days a week, and how much detail they recorded made no difference.

What doesn't work well is guessing by eye alone. In a survey run alongside Google's Nutrition5k study, people estimated the weight of food on 10 simple plates. Non-experts were off by 53 percent on average and nutritionists by 41 percent, even with reference weights to help them.

What can you use instead of a scale?

Use tools that already carry a measurement, and save guessing for the rest.

The deck-of-cards comparison comes from the American Heart Association. The label measures come from the FDA's labeling rules.

Which foods deserve the most care?

The calorie-dense ones, where a small misjudgment adds the most. According to USDA FoodData Central, a tablespoon of olive oil has about 119 calories, a tablespoon of butter about 102, and 2 tablespoons of peanut butter about 191. A cup of cooked white rice has about 205.

Compare that with a cup of chopped raw broccoli at about 31 calories. A heaping spoonful of peanut butter instead of a level one matters more than an extra half cup of vegetables. Measure fats, nut butters, dressings, cheese and grains first, and eyeball the salad.

How do you get better at estimating?

• Check your references once. Pour your usual bowl of cereal or rice into a measuring cup, and see what your usual glass holds. After that, you're comparing against a known amount.
• Read the serving size. The FDA points out that every number on the label refers to one serving, and that the serving size reflects what people typically eat rather than what you should eat. Eat the whole package of a 4-serving lasagna and you get 4 times the calories.
• Log as you go. In a 2019 study of an online weight-loss program, people who lost at least 5 percent of their weight opened their food journal 2.4 times a day on average, compared with 1.6 times for those who lost less.
• Use what restaurants publish. Chain restaurants must post calories on menus and provide more nutrition information on request.

How do you know if your estimates are off?

Watch your weight trend. The 2020–2025 Dietary Guidelines note that calorie estimates are only estimates and that the best way to judge intake against needs is body weight. If your weight doesn't move the way your log says it should over a few weeks, your numbers are probably running low.

That's common. In a 1992 study, people who said they couldn't lose weight on a low-calorie diet reported, on average, 47 percent less food than they actually ate. When the scale disagrees with your log, check the likely gaps first: cooking oil, drinks, snacks and second helpings.