Insulin may be best known as the hormone responsible for fat and weight gain. And although that’s true, there’s another hormone that’s just as influential when it comes to your body’s ability to control weight and burn fat. It’s called leptin. It’s a hormone you may have heard of before, since it’s intricately related to insulin. In fact, leptin works opposite to insulin - insulin stores fat and leptin burns off fat.
Insulin is secreted when you eat food, especially foods high in sugar, and it stores energy from food as fat in your body. Leptin is the hormone that allows your body to use the energy from fat. Interestingly what influences leptin is the amount of fat you have on your body. The more fat you have the more leptin will be available, so you can burn off the fat. But here’s the catch 22…as you burn off unwanted body fat and your stored fat decreases, it lowers your leptin levels.
Essentially as you lose more weight and get leaner, your leptin level gets lower, which makes burning fat and losing weight more difficult. Lower leptin levels also decrease your energy level making you feel sluggish and unmotivated to do much of anything. It’s a dilemma especially in modern times, but it makes sense when you look at it from an ancestral survival point of view. Lack of fat storage is seen as potential energy loss and hence a threat to your body’s survival, so your body knows to down regulate everything and conserve energy…which also means keeping your fat intact.
Fortunately (for most of us), we don’t have to worry about food scarcity which is absolutely wonderful. However, having modern conveniences and access to food 24/7 have caused an over indulgence of unhealthy foods leading to hormonal problems - namely insulin and leptin - and resulting in excessive weight and fat gain.
The good news is that cleaning up your diet by eating whole foods, eliminating refined foods, consuming proper ratios of macronutrients (protein, carbs and fat as recommended in my Lean Body Diet), and including exercise on a regular basis (MAX Workouts) will fix majority of your hormonal problems and enable you to effectively lose weight and burn off unwanted fat.
However, if you’ve done all that and after a few weeks of progressive weight loss and fat reduction you suddenly hit a wall and haven’t been able to move the number on the scale or reduce the number on your body measurements for sometime now…it may be because your leptin levels are too low.
Leptin for the most part only becomes an issue when your weight loss and fat reduction stalls after fixing your diet and you’ve been exercising on a regular basis for a while. If you’ve been following a lower carbohydrate diet (as suggested in my Lean Body Diet - part of the MAX Workouts Program) and restricting your carbohydrate intake to 100 - 150 g or less per day, you may have lowered your leptin to a point that your body is not able to effectively burn fat.
Although ineffective leptin function has more to do with low overall calorie intake than just low carbohydrate intake, for the most part, following a carb restricted diet will lower your total caloric intake as a result and potential making your leptin ineffective.
If this is the case, one of the best way to boost your leptin back into action, so it can start burning off fat again, is by increasing your carbohydrate intake for one to two days out of the week.
Some people call this a cheat day, but I like to think of it as more of a carb refeed day. You’re still eating high quality foods (not junk food) with good sources of nutrients, just foods that are higher in carbohydrate content. I would strongly recommend staying away from refined carbohydrate foods and still stick to whole foods like (peeled) potatoes, sweet potatoes and rice that have a dense carbohydrate content without the potential negative effects like gluten (wheat) and anti-nutrients (phytates).
The amount of carbohydrate you should eat will vary according to each individual. It depends on many variables such as your carbohydrate tolerance, your activity level and you body fat composition. In general, the leaner and more active you are, the more carbohydrate you can consume on your refeed day. Also the more you restrict carbohydrates on a regular basis, the more you can consume carbs on your refeed day as well. There’s always a delicate balance of science and art behind every diet and this is no different. It’ll more than likely take a few trial and errors to find out what works best for you. In general, I find that majority of people do fine with one carb refeed day per week or two consecutive carb refeed days every 10 - 12 days. And the carbohydrate intake can range from 250g up to 500g a day.
So if you’ve stopped progressing, even though your diet is really good and your fitness regimen is solid, you may be suffering from low leptin levels. If so, give carb refeed a try. A little boost in your calories by increasing your carbohydrate intake may just be what you need to kick start your fat burning and weight loss again!