It depends on what is meant by 'sugar free'. In theory, any recipe claiming it is sugar free should be OK for a low GI diet as long as it does not contain a significant amount of sugar alternatives such as honey, maple syrup, fructose, concentrated fruit juices or other highly refined carbohydrate foods such as white flour, white rice and white pasta, or large quantities of fruit juice.
In terms of low carb diets, the same holds true as far as sugar alternatives are concerned. However, grains are high in carbohydrates and even the 'good' versions of them such as whole grain flour, whole grain bread, whole grain pasta, brown rice and dried and fresh fruits which may be allowed on a low GI diet are usually unsuitable for a low carb diet.
Sometimes people look for sugar free recipes because they simply want to cut down on the amount of refined sugar they are eating. Other users of sugar free recipes are those following an anti candida diet. However, candida diets are usually yeast free, not just sugar free.
Diabetics are another group of people who look for sugar free recipes. In their case, what they are looking for in sugar free recipes is most likely to be similar to those following low GI diets.
All the recipes in the "Low Carb / Low GI Cookbook" are sugar free and because they are in addition very low carb and yeast free, they are also fine for diabetics and people following the candida diet.