>which would be the best to have ?50gm packect beef jerky or a bar of darrell lea milk chocolate ( zero carb sugar free)

I would say, be careful with the jerky. Most jerky manufacturers hide sugar in their marinade before they dehydrate the meat. So, even if it may not seem sugary, it probably is. It'll add carbs to your diet.

As far as the zero carb sugar free bar, you'll have to read the ingredients and decide for yourself. Simply because it says 'zero carb' doesn't necessarily mean this is so. Always check the ingredients for hidden sugars and starches.

If you're looking for snacks, nuts are really great. High in protein, medium in fat (good fat), low in carbs. Salted nuts sometimes have added modified food starch to hold the salt to the nuts (like glue). As far as a sweet snack, I bake almond cookies or drink lemonade sweetened with sacharrin/stevia. Peanut butter mixed with a little honey is also a great treat. Honey is a sugar, so use it sparingly (17g carbs per tablespoon).