To achieve weight loss—and maintain that healthy weight once you've achieved it—it's crucial to really understand what a portion is. Here's what may prove to be an indispensible tip: use your hand as a guideline for portion sizes.
Palm = Proteins
Make protein portions the size of your palm. Protein is found in animal products, like fish, meats, and cottage cheese. Some veggie protein sources include legumes (beans, etc.), tofu, tempeh, and wheat glutens.
Thumb = Fats
Fats are important, but they're also very dense, so match fat portions to the size of your thumb. Good fat sources are avocados, olive oil, nuts, and seeds.
Fist = Fruits, Grains, etc.
Your bread, fruit, cereal, rice, and grain portions should be about equal to the size of your closed fist. Remember that it's always preferable to consume whole grains.
Hand = Veggies
Open your hand and spread your fingers as wide as you can. That's a good vegetable portion. Raw vegetables are loaded with fiber and nutrients, and they contain very few calories.