Well no diet is completely free from side effects and you are bound to come across something or the other. There are several different low carb diets that are available and ingredients in each one will vary. Low carb diets are often supplemented with protein. One of the main problems of low carb diets is that many people tend to lose weight too fast. This is a significant problem as the body finds it very difficult to adjust to sudden change in weight and mass. This can lead to giddiness and nausea as well. Low carb diets are also a problem for those who have health issues such as heart problems.