If you want to lose fat, keep insulin at bay during inactive times. Sure, insulin is a potent inducer of amino acid uptake and protein synthesis, which makes it key to a muscular physique, but it's a double-edged sword.
Insulin is effective at driving carbs into muscle and liver tissue (good), but it's also equally good at directing carbs into fat tissue (bad). To get the best of both worlds, skip the carbs at breakfast and during the early part of your day if you train in the late afternoon or evening. Instead, opt to replace carbs with healthy fats and keep your protein intake constant. This means something like an omelet with spinach instead of a carb-laden breakfast.
That said, we don't want to catabolize muscle and end up looking like a dude fresh off Weight Watchers. When your workout comes around, introduce carbs to maximize recovery.
One study found that 50 grams of carbs in a workout drink consumed during a resistance training session completely eliminated cortisol elevations compared to a control drink. Subjects within this study with the lowest cortisol – and the greatest muscle gains – were entirely from the group who drank the carb drink, whereas subjects tested with the highest cortisol showed the least gains. (One placebo participant on the control drink even lost muscle size during the study.)
You want a workout nutrition drink (such as Plazma™) containing cyclic dextrin and fast-acting di- and tripeptides that digest quickly and turn on protein synthesis. Then you can follow up your workout with some complex carbohydrates – maybe even some fun ones in moderation – when your muscles are most sensitized to absorbing them.
- Tarpenning, K.M., Influence of weight training exercise and modification of hormonal response on skeletal muscle growth. J Sci Med Sport. 2001 Dec;4(4):431-46.1997.