Imitation crab meat is basically tilapia with a bunch of sugar and fillers added to make it look like crab. It's not something you should be regularly including in your diet. It has a lot of sugar, carbohydrates and fat per serving. It's especially not a good option if you are trying to loose weight.
The ingredients list on crab: Crab
The ingredients list on imitation crab: Alaska Pollock, Water, Egg Whites, Wheat Starch, Sugar, Corn Starch, Sorbitol, Contains 2% or Less of the Following: King Crab Meat, Natural and Artificial Flavor, Extracts of Crab, Oyster, Scallop, Lobster and Fish (Salmon, Anchovy, Bonito, Cutlassfish), Refined Fish Oil (Adds a Trivial Amount of Fat) (Anchovy, Sardine), Rice Wine (Rice, Water, Koji, Yeast, Salt), Sea Salt, Modified Tapioca Starch, Carrageenan, Yam Flour, Hydrolyzed Soy, Corn, and Wheat Proteins, Potassium Chloride, Disodium Inosinate and Guanylate, Sodium Pyrophosphate, Carmine, Paprika.
You basically have 2 options:
1. Buy canned crab meat. It's pretty affordable
2. Use canned tuna instead of crab. If you make crab cakes with canned tuna, it tastes literally the exact same.