We eat nutrition bars because we want to lead healthier lives, and yet are extremely busy. Plus, let's be honest, we eat them as an emotional substitute for candy bars.
We don't want to feel deprived of the sweet foods we want to eat, so we substitute a meal replacement bar that still tastes good but has a significant amount of vitamins and minerals and other health ingredients in it.
I personally prefer Balance Original bars, Sears Zone Nutrition bars and ZonePerfect bars, because these are the ones that provide the precise 40/30/30 (40% carbohydrates, 30% protein and 30% fat) that puts you in the Zone, keeping the hormone insulin not too high and not too low.
Some diet bars are so high in carbohydrates that, except for the vitamins and minerals, you may as well be eating a candy bar.
Protein bars are designed for people who want to cut carbs out or way down, or just people such as body builders and weight lifters who want to increase their muscle size. They're often not concerned about eating a balanced diet. They think that eating lots of protein along with their workouts will build the bulk they're looking for.
The Zone is the Jennifer Aniston diet plan she went on, that balance of all the macronutrients that are optimal for your health. It was first introduced to the world in 1995 by Dr. Barry Sears in his book THE ZONE.
One prominent brand of food bars is PureFit. They're kosher and vegan-approved. They don't contain any wheat, dairy or gluten. Each bar contains 18 Grams of Soy Protein, which is Non-GMO (Genetically Modified Organism). Each bar is 56.7 grams, which is larger than some other bars. They contain 220 to 240 calories.
They contain 24-26 g of carbohydrates and 18 g of protein. Therefore, they are not Zone favorable.
They come in the flavors: Berry Almond Crunch, Almond Crunch, Chocolate Brownie, and Peanut Butter Crunch.
Luna makes a line of food bars especially for women. They're 70% organic. They contain 8-9 grams of protein, along with various vitamins and minerals of course. They smaller than the average -- 48 grams, and have only 170-190 calories. They have 9-11 grams of sugar, but don't provide a total carbohydrate figure, and say they have a low glycemic index.

Luna bars come in many flavors: Lemon Zest, Berry Almond, Chai Tea, Caramel Nut Brownie, Chocolate Peppermint Stick, Chocolate Raspberry, Cookies 'N Cream Delight, Iced Oatmeal Raisin, Dulce de Leche, Nutz Over Chocolate, Peanut Butter Cookie, S'mores, Toasted Nuts and Cranberry, White Chocolate Macadamia, and Luna Minis.
Luna also has other lines of meal replacement and diet bars for women. Luna Sunrise is for eating in the morning. Those come in the flavors: Apple Cinnamon, Blueberry Bliss, Strawberry Crumble, and Vanilla Almond.
Omega Smart also carries nutrition bars. Their bars also contain fermented soy, flax seed, isoflavones, and acai berry (which isn't intended for weight loss, despite what the scammer say, but is still a powerful antioxidant, so it is healthy). Each Omega Smart bar gives you 1500 mg of omega-3 essential fatty acids.
Foods used in making their bars include figs, almonds, walnuts, Agave, dark chocolate and coconut.
Next: Protein Bars -- bars high in protein not carbs.