White rice is avoid because it's refined and not that good for you.
In general bodybuilders carb cut to lose fat and become more cut. You can become quite cut without carb cutting but to be cut enougth to enter competitions you generally have to carb cut. They don't carb cut to try and build muscle. When there building up there muscle they generally get plenty of carbs. Carb cutting has implications for your health because of what your replacing the carbs with., i.e. high protein/high fat diets.
High fat diets are as most people should know bad. You put on weight, have heart problems, circulation problems, diabetes etc etc. Generally in high protein diets it's hard, but not impossible, to avoid high levels of fat.
High protein diets also have various health problems. Protein causes the blood to become acidic. The body can't stand acidic conditions so it will attempt to nutralise it. It will use salt at first, and what that has run out it will take calcium from the bone, leading to weakened bones and osteoperosis. You can't just take more salt because high salt diets have there own health problems.
High protein diet also puts pressure on the kidney, as it tries to eliminate leage quanities of urea, a by-product of protein metabolism. This can lead to kidney stones, or evan kidney failure in extreme cases.
As your also trying to remove carbs your not going to be getting enougth of many essential nutrients contained in fruit and veg. In particular fibre. A low fibre diet means that food will remain in the digestive track for two to three days. Meat will start to rot in this time and release toxins. These toxins, among other complaints, can cause cancer.
Carbohydrates are also essential for good even energy levels. The body knows how to metabolism high carb diets as this is what it evolved on. Lack of carbs will reduce energy levels, cause mood swings, reduce concentration and reaction times.
Basically consider carb cutting as something like drinking alcohol. Bad for you, but if you want the results bad enougth you'll consider the risk worth it.
