Why? Because almost no one can track actual calories consumed very well. We think we can estimate well enough, but in reality we are typically under-reporting, and consuming more food than we imagined. Often a LOT more. This topic is discussed in the Under-Estimating Calories page.

Some people say, "It's easy: just eat 'reasonably sized' portions and you'll be fine". The problem is that "reasonably sized" is too vague and few people even know what that means. The size of the meal does not always correlate to the amount of calories. (See Fat Burning Foods for more about energy density of different foods.)

If you truly want to learn how much you are eating you simply cannot guess and estimate.

What Is "Counting and Measuring"? Basically it's whatever you need to do to figure out portion sizes, calories and amounts of nutrients (like carbs, fat, and protein). You do this by weighing, measuring, and looking at food labels. Calorie-counting apps can also be very helpful.

This process teaches you a lot about nutrition and calories! After you've measured and calculated accurately for awhile, you will begin to get a better sense of quantities and amounts. Then you can more easily eyeball and estimate.

You should be counting/measuring at least temporarily if:

You're having trouble losing and suspect you might be eating more than you think
You wonder if you are not eating enough
You have never counted calories or measured food before
You don't know how to read a Nutrition Facts Label
You are just beginning a program that refers to specific amounts and portions

Counting and Measuring helps you with:

Total calories you are aiming for
Restricted or limited food (like carbs or fat)
Food that you are trying to get more of (vegetables, etc)
Food you need a specific amount of (protein, etc)

Do I have to do this forever? No. If you enjoy it or if it's a positive experience for you, by all means continue. But, mainly do it to become more aware.

Track, count and measure until you get comfortable with it and a have an accurate handle on amounts and calories. If you absolutely hate counting calories and portions, try it for at least 3 - 7 days or a week. You will often be shocked at the numbers you end up with. Again, it is very educational and some of the most valuable knowledge you can have when trying to lose weight.

Bottom line: Use counting and measuring as an awareness tool, to get an accurate picture of how much you're really eating. But there's no need to be super strict and count every little thing forever because that's not practical or sustainable.

Tools for Accurate Measuring and Counting

Kitchen items:

Kitchen scale
Measuring cups and spoons

Label information:

Pre-packaged portion-controlled food (e.g., frozen dinners, snack items)
Apps with bar-code scanners
Nutrition facts labels for calorie density calculations

Calorie counting apps:

There are many of them out there, such as My Fitness Pal, Chronometer, and Carb Manager.

Estimating Food

Here are some methods of estimating:

Plates, bowls, glasses:

Use measuring cups to pour liquid into bowls or glasses, or solid food onto plates, so you know how much they hold. That makes it easier to quickly eyeball amounts in the future.

Hands:

Your fist is about the size of 1 cup (unless you have very large hands)
The palm of your hand is roughly the size of 3 ounces of meat

Everyday objects:

Deck of cards: about 3 ounces of meat
Lipstick tube, or 6 dice: about 1 ounce (e.g., for cheese)
Baseball: about 1 cup (e.g., for cereal)
Ping-pong ball: about 2 tablespoons of peanut butter

Estimating Protein

You can estimate protein fairly simply by using the following guidelines:

As mentioned above, three (3) ounces of meat is roughly the size of your palm or a deck of cards
On average, raw meat contains 6 grams of protein per ounce
On average, cooked meat contains 8 grams of protein per ounce

This kind of estimation won't be completely accurate but it's often close enough.

Example, to calculate protein in two palm-sized portions of raw meat, you know it weighs roughly 6 ounces (3oz x 2 palms), so it contains 36 grams of protein (6oz x 6g).

For estimating the content of other protein sources, you can use the following numbers:

Beef jerky contains 10 grams of protein per ounce.
Cheese contains 8 grams of protein per ounce.
Cottage cheese contains 14 grams of protein per ounce.
Egg whites contain 3.5 grams of protein per egg.