Conjugated Linoleic Acid for Weight Loss?

You asked us to evaluate the use of CLA for weight loss, so that’s today’s main feature!

First, what is CLA?

Conjugated Linoleic Acid (CLA) is a fatty acid made by grazing animals. Humans don’t make it ourselves, and it’s not an essential nutrient.

Nevertheless, it’s a popular supplement, mostly sold as a fat-burning helper, and thus enjoyed by slimmers and bodybuilders alike.

❝CLA reduces bodyfat❞—True or False?

True! Contingently. Specifically, it will definitely clearly help in some cases. For example:

• This study found it doubled fat loss in chickens
• It significantly increased delipidation of white adipose tissue in these mice
• The mice in this study enjoyed a 43–88% reduction in (fatty) weight gain
• Over the course of a six-week weight-loss program, these mice got 70% more weight loss on CLA, compared to placebo
• In this study, pigs that took CLA on a high-calorie diet gained 50% less weight than those not taking CLA
• On a heart-unhealthy diet, these hamsters taking CLA gained much less white adipose tissue than their comrades not taking CLA
• Another study with pigs found that again, CLA supplementation resulted in much less weight gained
• These hamsters being fed a high-cholesterol diet found that those taking CLA ended up with a leaner body mass than those not taking CLA
• This study with mice found that CLA supplementation promoted fat loss and lean muscle gain

Did you notice a theme? It’s Animal Farm out there!

❝CLA reduces bodyfat in humans❞—True or False?

False—practically. Technically it appears to give non-significantly better results than placebo.

A comprehensive meta-analysis of 18 different studies (in which CLA was provided to humans in randomized, double-blinded, placebo-controlled trials and in which body composition was assessed by using a validated technique) found that, on average, human CLA-takers lost…

Drumroll please…

00.00–00.05 kg per week. That’s between 0–50g per week. That’s less than two ounces. Put it this way: if you were to quickly drink an espresso before stepping on the scale, the weight of your very tiny coffee would cover your fat loss.

The reviewers concluded:

❝CLA produces a modest loss in body fat in humans❞

Modest indeed!

See for yourself: Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans

But what about long-term? Well, as it happens (and as did show up in the non-human animal studies too, by the way) CLA works best for the first four weeks or so, and then effects taper off.

Another review of longer-term randomized clinical trials (in humans) found that over the course of a year, CLA-takers enjoyed on average a 1.33kg total weight loss benefit over placebo—so that’s the equivalent of about 25g (0.8 oz) per week. We’re talking less than a shot glass now.

They concluded:

❝The evidence from RCTs does not convincingly show that CLA intake generates any clinically relevant effects on body composition on the long term❞

A couple of other studies we’ll quickly mention before closing this section:

• CLA supplementation does not affect waist circumference in humans (at all).
• Amongst obese women doing aerobic exercise, CLA supplementation has no effect (at all) on body fat reduction compared to placebo

What does work?

You may remember this headline from our “What’s happening in the health world” section a few days ago:

Research reveals self-monitoring behaviors and tracking tools key to long-term weight loss success

On which note, we’ve mentioned before, we’ll mention again, and maybe one of these days we’ll do a main feature on it, there’s a psychology-based app/service “Noom” that’s very personalizable and helps you reach your own health goals, whatever they might be, in a manner consistent with any lifestyle considerations you might want to give it.

Curious to give it a go? Check it out at Noom.com (you can get the app there too, if you want)

A Sliding Slope?

In Tuesday’s newsletter, we asked you how much control you believe we have over our sleep schedule, and got the above-depicted, below-described, set of responses:

• 45% said “most people can control it; some people with sleep disorders cannot
• 35% said “our genes predispose us to early/late, but we can slide it a bit
• 15% said: “going against our hardwired sleep schedules is a road to ruin”
• 5% said “anyone can adjust their sleep schedule with enough willpower”

You may be wondering: what’s with those single-digit numbers in the graph there? And the answer is: Tuesday’s email didn’t go out at the usual time due to a scheduling mistake (sorry!), which is probably what affected the number of responses (poll response levels vary, but are usually a lot higher than this).

Note: yes, this does mean most people who read our newsletter don’t vote. So, not to sound like a politician on the campaign trail, but… Your vote counts! We always love reading your comments when you add those, too—often they provide context that allow us to tailor what we focus on in our articles

However, those are the responses we got, so here we are!

What does the science say?

Anyone can adjust their sleep with enough willpower: True or False?

False, simply. It’s difficult for most people, but for many people with sleep disorders, it is outright impossible.

In a battle of narcolepsy vs willpower, for example, no amount of willpower will stop the brain from switching to sleep mode when it thinks it’s time to sleep:

❝Narcolepsy is the most common neurological cause of chronic sleepiness. The discovery about 20 years ago that narcolepsy is caused by selective loss of the neurons producing orexins sparked great advances in the field

[There is also] developing evidence that narcolepsy is an autoimmune disorder that may be caused by a T cell-mediated attack on the orexin neurons and explain how these new perspectives can inform better therapeutic approaches.❞

~ Dr. Carrie Mahoney et al. (lightly edited for brevity)

Source: The neurobiological basis of narcolepsy

For further reading, especially if this applies to you or a loved one:

Living with Narcolepsy: Current Management Strategies, Future Prospects, and Overlooked Real-Life Concerns

Our genes predispose us to early/late, but we can slide it a bit: True or False?

True! First, about our genes predisposing us:

Genome-wide association analysis of 89,283 individuals identifies genetic variants associated with self-reporting of being a morning person

…and also:

Gene distinguishes early birds from night owls and helps predict time of death

Now, as for the “can slide it a bit”, this is really just a function of the general categories of “early bird” and “night owl” spanning periods of time that allow for a few hours’ wiggle-room at either side.

However, it is recommended to make any actual changes more gradually, with the Sleep Foundation going so far as to recommend 30 minutes, or even just 15 minutes, of change per day:

Sleep Foundation | How to Fix Your Sleep Schedule

Going against our hardwired sleep schedule is a road to ruin: True or False?

False, contextually. By this we mean: our “hardwired” sleep schedule is (for most of us), genetically predisposed but not predetermined.

Also, genetic predispositions are not necessarily always good for us; one would not argue, for example, for avoiding going against a genetic predisposition to addiction.

Some genetic predispositions are just plain bad for us, and genes can be a bit of a lottery.

That said, we do recommend getting some insider knowledge (literally), by getting personal genomics tests done, if that’s a viable option for you, so you know what’s really a genetic trait (and what to do with that information) and what’s probably caused by something else (and what to do with that information):

Genetic Testing: Health Benefits & Methods

Take care!