As of this writing,
the dominant theory on human health appears to be: Eat very little, limit
carbohydrates, and do mostly strength training. Or, perhaps it would be more
accurately summarized: ketosis and weight lifting.
Advocates of this
approach recommend training your body to metabolize protein and fat in its
resting state, so that you don't risk carrying a lot of body fat. While many
people who follow keto-style diets don't have the whole story on why
cardiovascular exercise is generally avoided by keto practitioners, the idea
there is that, since cardiovascular exercise promotes fat matabolism, and
therefore some fat storage, cardiovascular exercise is bad for losing weight.
Besides, many will continue, weight lifting burns just as many calories and
building more muscle mass means increasing your body's Basal Metabolic Rate
(BMR). So, even though exercising doesn't hold a candle to dieting for weight
loss, building more muscle mass is better than not building that muscle mass.
Even if the BMR boost is small, it's still positive. Meanwhile, remaining in
ketosis will take care of all that pesky fat tissue. Play your cards right, and
you'll soon look like Ronnie Coleman, or so the argument goes.
(Never mind that
Ronnie Coleman never actually ate like that.)
Under this paradigm,
a person will eat mostly meat and vegetables, and very little of anything else,
while doing some daily weight lifting. This is certainly a much healthier
lifestyle than the average American is currently living, so if you're the kind of
person to whom this lifestyle appeals, I say go for it.
Even so, I'd like to
present you with a viable alternative that is at
least as healthy, and possibly a lot
healthier. That lifestyle can best be summarized as: do a lot of hard
cardiovascular training, and eat a Mediterranean/DASH type diet consisting of
lean meats, plant-based unsaturated fats, and whole grains. And don't go into
The first reason I
recommend this kind of lifestyle over the keto/weight-lifting lifestyle is
because it is precisely the kind of lifestyle recommended by every doctor and
dietician worth their salt. The second reason is because it is the only diet
and fitness lifestyle that is consistently supported by scientific evidence.
But if that isn't
enough to convince you, then consider a few more things.
Let's tackle the
question of burning fat. A keto practitioner aims to burn fat and metabolize
protein while his body is at rest. An endurance athlete, by contrast, aims to
burn fat during exercise. The sweet-spot for this starts after twenty minutes
of cardiovascular exercise and continues for up to about ninety minutes before
tapering off. So, any cardiovascular activity you engage in that lasts between
20 and 90 minutes will primarily metabolize fat. If you have 45 minutes today,
you can burn a bunch of fat cells and still eat fruit and drink milk and have a
little pasta. There is no need to sacrifice pleasant and healthy food like
blueberries and whole grain toast in order to burn fat off your body. You just
need to spend between 20 and 90 minutes, several times per week, burning fat as
fuel for exercise.
I grant that ketosis
will enable you to do this while at a resting state. But the science of the
matter is that you don't have to, and
having that other option just might appeal to you. Especially if you like
What about increased
muscle mass and an elevated BMR? Won't you have to give those up if you focus
on cardiovascular exercise? No. The reason is because cardiovascular activities
like running, swimming, and cycling still build lots of muscle; it just happens
to be a smaller-yet-denser muscle tissue, compared to the hulky fast-twitch
tissue required for weight lifting. In other words, endurance athletes still
have more muscle mass and higher BMRs than sedentary people, even though their
muscles appear smaller.
You might prefer the
aesthetic appearance of a linebacker to that of a marathoner, and if so, more
power to you. Lift weights. But, if you've been eschewing cardio exercise under
the impression that you won't be as healthy as you will if you stick to weight
lifting, then I have some good news for you: Do all the cardio you want, you'll
still build muscle mass and enjoy a higher BMR.
A final important
consideration here is the impact of cardiovascular fitness on longevity. As of
my writing this, there is little evidence to support the notion that lifting
weights extends your lifespan; but there is solid evidence in favor of the
notion that cardiovascular health makes you live longer. So, if your goal is
not only to lose weight and be healthy, but to live a longer life,
cardiovascular exercise offers you something keto + weight lifting cannot.
So, which paradigm
is for you? Burn fat while resting and never eat a carbohydrate? Or burn fat
while exercising and eat tons of fiber? The choice is yours. I know what I've