Sugar is sugar...also known as dextrose,fructose,sucrose...if it ends in 'ose' its sugar. Even added to foods like deli meats,sausages,even cheese!
The so called caveman or paleo diet is not the same as dukan. Dukan is low carb and low fat...which is a bad combination. The point of reducing carbs is to get the body to burn fat...and you need to eat fat to burn it,whereas using carbs for fuel means the bnody holds on to its fat stores. Paleo is eating unprocessed foods...fresh meat,fish,poultry,eggs,good fats from nuts,seeds,olive oil,butter,lots of veg,not too much fruit. No grains because its believed that we have not evolved to eat grains,and that grains contribute to a lot of modern illnesses. The current rise in obesity can be traced back about 40-50 years when some badly done research came to the conclusion that eating fat led to heart disease...this has never been proven. Its so called low fat foods that will make you fat...along with high carb foods including grains (which are used in animal feed to...guess what??...make them fat).