Are low carb high fat diets bad? you can lose lots of weight, but is a long term approach not good for your health?

Not necessarily: This depends upon the fats eaten. Make sure they are good fats and the low CHO portion should be low in simple carbohydrates. Search simple carbohydrates and unhealthy fats, and avoid them.

Dr Machanic agreed

Controversial: Best Health diet is to lower calories to a reasonable level, not high fat or low carbs. I cannot advise how many calories, depends on size. High fat low carb diets work but lead to no energy. Also helpful to get 20+ minutes of mild-mod exercise a day - or keep active (walking etc), and drink plenty of water. If you eat too little your body will go into a low calorie burning state.