A very effective diet, if you can't handle low carbs, is the intermittent fasting or the carb cycling diet where you eat large amounts of carbs periodically. (fitnessandpower.com)
To build muscle in most effective way bodybuilders cycle their diet and supplementation. (massgainsource.com)
And because the protein in carb cycling diets is relatively high, you will be retaining much more muscle mass or even gaining a little. (chriscoulsonfitness.com)