One key point that’s overlooked in some of the research is that fat is burned in the presence of glycogen. Even a small meal will help “prime the fat burning pump”. For that matter, even a small amount of quality liquid calories ( milk’s a great choice! ) will suffice.
In related research, some studies are suggesting that eating a meal high in carbohydrates post-workout decreases fat burning. Indeed, drinking or eating a lot of sugar or simple carbs raises insulin levels which encourages body fat storage. Now this makes sense as research has shown that a balanced meal featuring a combination of complex carbs and protein is best for restoring glycogen stores–not fat stores- after exercise. Ideally, pre-and post-workout snacking should also consist of a balanced mini-meal of complex carbs, lean protein and a little healthy fat.
I think the jury is still out with regard to the research on eating, exercising and fat burning. While exercising on empty may potentially increase fat-burning, if you have no gas in your tank you’re less likely to exercise as long or as vigorously and there goes the extra fat and calories you might have burned. My advice: fuel up with high-quality, nutritious foods and beverages before and after exercise and your engine will perform better in the short and long run.