You may be one of those poor bastards that retains a roll of fat around his waist no matter how much you diet and how lean you get. That "tubey" look may reflect insulin resistance.
While your instinct might be to adopt a low-carb diet, it doesn't fix the problem. What's more, a chronic low-carb diet leaves your muscle-building capabilities impaired. What you need to do instead is optimize insulin sensitivity:
At the start of a meal, eat some protein and fat before you even touch any carbohydrate. This strategy, according to research, leads to significantly lower blood sugar levels (29%, 37%, and 17% lower at 30, 60, and 120 minutes after a meal) than eating carbs first. (You should, however, flip-flop the strategy during meals around your workout and eat some carbs before eating protein.)
Take 400 to 600 mg. of Cyandin 3-Glucoside (C3G) before your biggest meal of the day. C3G is a naturally occurring anthocyanin. When isolated and taken in hugely concentrated form, it has powerful blood-glucose lowering properties that can go a long way in treating the fat waist caused by insulin insensitivity.
Use high-quality fish oil liberally. New studies show that not only does it rival the effects of exercise on blood sugar, but when combined with exercise, actually has a synergistic effect on blood sugar reduction.
Take two tablespoons of apple cider vinegar before bed, as studies have shown that it can lower morning blood sugar by 4 to 6 percent.
Take one teaspoon of psyllium fiber twice a day. It can lower all-day blood sugar levels by 11 percent.