Dear Mark: Should I Increase Carb Intake for Weight Loss?
Mark’s Daily Apple
by Mark Sisson: More
weight loss slows. Sometimes, what worked amazingly well before,
stops working quite the same. Although this can be scary, frustrating,
annoying, or all of the above when progress
slows, stops, or requires new input to continue like it was
is ultimately okay, because we are an adaptive species. We can change
things up, shift stuff around. Physiological processes (among
which weight loss and metabolism can certainly be counted) are never
linear – that's partly what makes all this stuff so endlessly
Today, I revisit
a strategy for overcoming these lulls in weight loss induced by
low carb: carb (re)feeds. They seem counterintuitive, sort of, especially
if you've had success restricting carbs, but hold you opinions until
you read on. I think you'll find it enlightening.
Your blog is a treasure trove of valuable information. Thank you
for keeping this resource available to us!
This is a
question that I think many of your readers would appreciate seeing
addressed in a post. [Background: I've been studying (and trying,
periodically) various low carb regimens for many years, with varying
degrees of success. I'm looking to metabolize off about 30-40
pounds of excess fat, build lean muscle and optimize my health
is, what do you think of the increasingly common recommendation
(from various diet and fitness gurus) to "spike" calories and
carbs one day per week, in order to keep the body from down-regulating
certain mechanisms too much due to continued low carbohydrate
intake? The theory is that a once-per-week carb/calorie spike
gives the metabolism a boost, and keeps weight loss going at a
better rate than simply sticking to the low carb regimen seven
days per week.
if this recommendation for one "free day" per week is helpful
or harmful to the objective of significantly reducing excess body
fat over a period of a few months, and staying lean for life.
I don't mean a "be a fool and eat garbage" day, but an honest
"spike the carbs and calories with healthy foods" day. What do
you think: Would this be a weight loss booster overall, or just
a setback on the road to burning excess fat and getting to an
optimally lean body composition?
I (and I'm sure your other readers) will value your opinion on
happy to help. Thanks for the kind words.
answer: Yes, I think there is something to the lowish-carber's
occasional carb and calorie fest. Its relevance to a given individual
depends on that person's metabolic situation, of course, but I wouldn't
dismiss it out of hand. Check out my previous posts on leptin
refeeds and weight loss to get an idea.
answer: If you're eating low-carb and low-calorie (which
low-carb tends to promote on account of its inherent satiety) and
the weight has stopped dropping, you may be low in leptin. Why does
leptin matter, and what do calories and carbs have to do with it?
Leptin is a
hormone that fulfills two primary roles, as far as metabolism and
weight loss go – it increases (or lowers) energy expenditure, depending
on perceived energy availability, and it inhibits appetite. Both
actions actually happen in the brain, but it's leptin that gives
the brain the message. If perceived energy availability is "low,"
energy expenditure drops and appetite increases. If perceived energy
availability is "high," energy expenditure increases and appetite
drops. That's a quick and dirty (and incomplete) overview, but it
serves our purposes for today's discussion.
How does the
body "perceive" energy availability?
Body fat is,
quite literally, stored energy. It's also an endocrine organ
that secretes leptin, the amount of which in circulation is directly
proportional to the amount of adipose tissue on your body.
So, the leaner you get, the less body fat (and less stored energy)
you have available to drive leptin secretion. Even if you're not
as lean as you'd prefer to be, your lower body fat levels are low
enough that the brain isn't getting the "high energy availability"
message from leptin.
is another indicator of energy availability. Sure enough,
increases leptin secretion in fat cells. As far as the body's
concerned, if insulin is present in significant amounts, food has
just been eaten, which means food is probably available in the environment.
If food is readily available, the body doesn't need to cram as much
food in, nor does it have to conserve energy. It can do things that
aren't essential to immediate survival, like play a game, have sex,
go explore, or work out, because there's plenty of energy available.
Leptin goes up, reducing appetite and increasing expenditure. Problems
arise with leptin resistance, of course, when your insulin
is constantly elevated, but I'll get to that later.
content of the diet, perhaps independently
of the increase in insulin, also affects leptin levels. Protein
also increases leptin, and fat seems not to, but carbohydrates have
the largest effect.
calorie content of the diet is an indicator of energy availability.
Studies show that calorie
restriction causes the body to lower serum leptin levels in
order to protect against further weight loss, and that supplementary
leptin kickstarts weight loss all over again.
the rest of the article
to Lew's recent podcast with Mark Sisson
August 1, 2012
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