I posted last week about wanting to lose weight while on Paleo. Someone responded with this suggestion: "Manage leptin sensitivity by overeating safe starches and fruits once a week." This was new to me and I asked for details, but didn't get any.
Currently I am trying to lose about 11 pounds to get back to my pre-pregnancy weight. I am not nursing and am still on a 30 day challenge diet (37 days of the challenge now...not sure I want to add anything in). I went low-carb a couple of weeks into the challenge because I wasn't losing as much weight as expected. Not sure it's helped at all. I've lost 4-5 pounds in the last 37 days.
Is the suggestion given a good one? And if so, any guidelines as to how to do it? Or information on how it would help? Thanks!
This person was probably referring to the research that shows leptin levels dropping (and thereby metabolic rate) from decreased food intake and from lowered body fat levels, and how short-term carbohydrate overfeeding seems to increase leptin levels.
Things that Impact Leptin:
Martin Berkhan says:
"The other argument, about tricking your body into fat-loss mode, usually alludes to the effect of overfeeding carbs on leptin. For a lean person, or for someone one a prolonged dieting stint, low leptin is an issue. This hormone, the king of hunger regulation, controls metabolic rate, appetite, motivation and libido, among other things. Leptin drops whenever your body senses a calorie deficit and when fat mass is lost.
The reverse happens when your body senses a calorie surplus. A surplus temporarily boosts leptin, which leads to downstream effects on fat oxidation, thyroid, dopamine and testosterone. In the context of dieting, refeeds are therefore beneficial.
However, similar to the effects of overfeeding on metabolic rate, a leptin-boost is also rather transient and drops again once you resume your diet and your body senses the deficit. It's for this reason I prefer to use frequent but moderate overfeeding, or refeeds, as part of the Leangains approach. Usually in conjunction with weight training to take advantage of the anabolic effects.
Here's a link to the study on carbohydrate overfeeding and leptin.
Leptin is the master hormone of the body that controls the rest. Insulin answers to leptin. You can effect energy balance or weight loss with controlling leptin. Leptin resistance occurs because of several reasons. The most common in the US is generation of excess AcetylCoA from fructose breakdown. Infect fructose induces genes that glucose does not and that activation up regulates a little used pathway called de novo lipogenesis. The Acetyl CoA collect at very rapid rates so the liver responds by making all this Acetyl CoA chained together to make palmitic acid. Ironically this acid is a saturated fatty acid but entirely made from carbohydrates substrate. This fat is the signal causes leptin resistance in the brain and not allowing for any weight loss. As leptin resistance builds it turn off fat burning in muscles as well. As leptin resistance increases it raised a brain neuropeptide called NPY and NPY stimulates cravings for all Carbs. More carbs mean more fat....because insulin resistance builds and weight gain occurs and makes it impossible to lose weight even if you exercise and calorie restrict.
I think that its a great suggestion, considering that you only have 11 pounds to lose. I am also on the last 10 pounds and I do 5 days a week of low carb paleo, followed by 2 days of higher carb paleo - Kumara (sweet potato) fries, pumpkin, etc. However, I have read that it's best to avoid fructose and only stick with starches.
I typically gain 2 pounds the day after "carb up" but then a couple of days after I drop those pounds + an additional pound or 2. Then the weight loss bottoms out towards the end of the 5 low carb days, then rinse and repeat. I find that it keeps my energy up, rather than sticking to low carb all the time.
No excercise, only walking, since I don't own a car (I walk everywhere) and maybe do callanetics 2 times a week.
Everyone responds differently; men may be less likely to have weight plateaus on paleo than women. Occasional high carb days (similar to Tim Ferris' "slow carb diet") might help you. I would also recommend intermittent fasting once you have been on paleo for awhile and your body has become used to overall better nutrition than you were likely to have been getting previously.
You may be at a weight that is healthy for your body but greater than you want. Going below a healthy set point can be a challenge.
You probably wanna stick with starches if you wanna make yourself leptin sensitive. Fructose will mess with your leptin sensitivity. HFCS, excess fruits, and stuff like agave nectar, along with sugar will induce leptin insensitivity.
The suggestion is intriguing because starches will make you hungry! Safe starches like yams, sweet potatoes and yuca have almost zero sugar (and fructose). But they're pure carbs so it will elicit an insulin response. When your BG goes back to the fasting level, 2 hours post prandial, you'll feel hungry.
Now, is this perhaps a way of restoring leptin sensitivity? I don't know. Many people cannnot exercise self-control with safe starches either! People always complain about gaining weight. But then it's abundantly clear that those indigenous peoples around the equator who habitually ate safe starches never suffered from chronic diseases like CVD or diabetes.
My answer is essentially the same as Tyler's. Leptin will rise in response to a carb refeed, but it goes down again right away when you reduce the carbs again.
The other side of the argument is best represented by Lyle McDonald, who has an excellent series on leptin, starting here:
http://www.bodyrecomposition.com/fat-loss/the-hormones-of-bodyweight-regulation-leptin-part-1.html He advocates refeeds, and his work contains the most cogent arguments for them that I know of. I'm still skeptical, though, at least about the role of leptin in this process.