The Dutch weightconsultant Sonja Bakker has written books like "Reach your ideal weight!" and "Reach and maintain your ideal weight". All describe a method to lose weight. To assess your weight you can calculate your BMI.
The Sonja Bakker method has strict rules as a basic menu, you must follow a number of weekmenus discribed in the book. You can switch a whole day menu, but not vary between breakfast of different days. The diet is based on 3 main meals and has a limited number of low-calorie snacks. The amount of calories in this diet is sufficiently low in order to get rid of kilos.
Like many diets, there are also comments about the opinions and "facts" in the books. For example Sonja Bakker recommends that no matter what you drink more, every day to drink 2 liters of water. This is absolutely not necessary. An adult needs per day 1.5 liters of drink. This can be water, but also tea, juice or other beverage.
Sonja Bakker works with many expensive branded products, while in many cases all brands of that product are good. Thus all fat dairy products without added sugar and all types of spreads good and not just the named brand product.
Finally, there are scattered through the book nutritional facts and tips that are inconsistent with scientific research, such as white wine get cellulite "," fruits cleanse your body" and "coffee extracts moisture from the body". This also applies to the advice that you would better eat an apple dumpling with a puff pastry (570 kcal) than eat 2 donuts (together 320 kcal).