Last year, for the first time of my life I went for a
diet - it was a high
protein,
low-carbs
diet, and I really got rid of all the extra pounds and even more. For that time I also did fitness and swimming. It took me 6 months to get rid of my extra weight, and bear in mind, that were only 22 lbs, meaning they were not too much.
If you want to lose weight being 100% sure no side effects would occur, then you should be prepared for a long weight loss process.