Ahh fat burn…a topic that twists people’s hairs out yet is persistently longed for. No worries though, I’m here to help calm your nerves and ease your way into shredding fat that doesn’t seem to want to leave.
We all wish for fat loss – it’s the only way to bring out those 6 packs! We also feel lighter, healthier and more confident the less fat we carry. Of course, nothing comes easily. To consistently burn fat is a long and tedious process requiring persistence, commitment, and a change in lifestyle.
In my previous post on fat burn, I provided a few strategies to enhance your body’s fat burning capacity. Here, I will do the same -offering other approaches you can employ to help you burn fat.
Before I proceed, I want to take a step back and briefly explain to you the carbohydrate response in the body. Upon digestion, carbohydrates transform into glucose (sugar) and have two fates: storage or usage. In either case, insulin (a hormone) is released from the pancreas to decide glucoses’ fate. In the case of an excess carbohydrate intake, insulin will store glucose as fat. If adequate carbohydrates are consumed, insulin will use up glucose for energy use or store the carbohydrates in the muscle rather than letting it flow in the blood stream (which would lead to fat storage otherwise). In all cases, the release of insulin (due to carbohydrate intake) inhibits the activation of enzymes responsible for lipolysis – the oxidation (burning) of fat.
Now onto the strategies.
I want to reiterate the notion of fasted cardio – or training first thing in the morning prior to consuming your first meal. I highly advise you to implement this strategy first and foremost. It’s a great stepping stone to adapt your body to burn fat for energy. To increase the extent of fat burn even further, limit your carbohydrate intake during dinner the night before, or at least make sure you leave a gap of 6 or more hours between your last carbohydrate-containing meal and the exercise session. Why? Evidence suggests that the negative effects of carbohydrate consumption (the release of insulin and eventual block on fat burn) can last up to six hours post-meal (Montain et al., 1991). Put simply, if you eat a carbohydrate-containing meal and work out less than 6 hours after, your body will continue to burn carbohydrates for energy.
Now, given that insulin is a potent blocker of fat burn, one approach you can take (if you can’t let go of the carb) is to manipulate the type of carbohydrates you eat. Essentially, there are two types of carbohydrates, those with a high-glycemic index (GI) and those with a low-glycemic index. The difference? Well, a low GI food does not produce a huge sugar spike like high GI foods. Hence, more fat will be available for energy use after consuming low GI carbohydrates due to the lower sugar spike, as opposed to consuming a high GI food that would significantly raise insulin production and increase the utilization of sugar for energy rather than fat. Point being – fat burn will be greater during exercise if low GI foods are consumed prior to exercise.
Your pre-exercise meal is not the only important factor to consider. Your post-exercise meal is equivalently significant for fat burn. Indeed, your body burns fat at rest. Depending on your exercise duration and intensity, your body may continue to burn fat to bring your body functions (i.e. heart rate and temperature) back to its normal state. However, if you consume carbohydrates, especially high GI foods, after exercise, then your body will use carbohydrates for energy (due to the insulin spike). In fact, a study showed that fat oxidation was reduced by 30% eight hours after carbohydrates were ingested post-exercise (Schneiter et al., 1995). That’s hella amount of fat being stopped from burning! That said, limit your carbohydrate intake post-exercise as well to allow the continual oxidation of fat.
In summary, for those wishing to burn fat, implement the following strategies for maximal rates of fat oxidation:
- Train on an empty stomach and leave a gap of 6 or more hours between your last meal (if it contained carbohydrates).
- If you prefer to eat carbohydrates prior to exercising, consume low GI foods to minimize the release of insulin.
- After exercise, limit your carbohydrate consumption to further decrease the release of insulin and allow for fat burning.
Montain, S.J., Hooper, M.K., Coggan, A.R. & Coyle, E.F. (1991) Exercise metabolism at different time intervals after a meal. Journal of Applied Physiology 70, 882-888.
Schneiter, P., Di Vetta, V., Jequier, E. & Tappy, L. (1995) Effect of physical exercise on glycogen turnover and net substrate utilization according to nutritional state. American Journal of Physiology 269, E1031-E1036.