That depends on what you want from your food choices. At least one well-designed study has found that bars advertised as “low-carbohydrate” produce an insulin response in the blood the same as a sugar-filled candy bar.
In this study, the researchers asked 20 adults to eat one of five test meals on five separate days; a low-carbohydrate energy bar (Atkins Advantage Bar); a moderate-carbohydrate energy bar (Balance Bar - Zone diet), a high-carbohydrate energy bar (Power Bar); white bread (which is nearly all carbohydrate); and broiled chicken breast (contains no carbohydrate).
Blood samples before and after consuming these meals provided blood glucose and insulin level readings. The white bread and the chicken-only meals are foods at both ends of the blood sugar/insulin scale - they are used to measure and compare the insulin response caused by other meals.
Results showed that both the low-carb bar and the moderate-carb bar produced blood insulin levels similar to that seen with the bar containing a lot of sugar. The high insulin response caused by eating the reduced carbohydrate bars show us that carbohydrate is not the only macro that raise insulin levels.
Most “low-carbohydrate” bars simply replace the carbohydrate with fat (glycerol). The overall energy content of low-carb bars is similar to that of higher carbohydrate bars. None of the manufacturers of low-carbohydrate snack foods have the data to support the claim that their products keep after-meal insulin levels low.
This study, showed that low-carbohydrate food bars produce an insulin response that is no different to that seen with sugar-laden candy bars.
Now don't get me wrong, I'm not slamming protein bars or food manufacturers for making bars. Just beware of the claims made, particularly if you are eating to improve your body shape.
Source: Medical Science Monitor