Monica Reinagel: I’ve written a lot about the connection between sleep and hunger, appetite, and weight management. But I’m looking at this problem as a nutritionist. How do you see the relationship between sleep, appetite, and weight management as a sleep expert?Jade Wu:  When we are sleep deprived, the body compensates for lack of energy by craving more calories and tends to reach out for more saturated fats, carbs, and sweets. We also have less leptin and more ghrelin levels in our blood after a night of not enough sleep, which is how these hormones behave when we’re very hungry.

What’s less talked about is the role that our circadian clocks play in all of this. We all have biological clocks that follow a roughly 24-hour rhythm, and these clocks love to run on time. Having a disrupted circadian rhythm (jet lag, shift work) can slow down our metabolism, make us crave more high-fat foods, and generally increase the stress on our bodies.

Psychologically, this stress from a disrupted body clock (together with the stress of insufficient sleep) makes us less motivated to stick to healthful behaviors… it makes us more cranky so we’re more likely to eat as a way of regulating our emotions… it makes us less energetic and less likely to be active.

So there are both biological and psychological ways that insufficient sleep and a disrupted circadian rhythm can affect weight loss and nutrition.

MR: Most of us the basics of good sleep hygiene (avoiding screens, caffeine, alcohol, keeping a consistent schedule, cool, dark rooms, etc.). But a lot of people still struggle to sleep through the night, despite taking all of those steps. You’ve suggested that sleep hygiene may not be all that. So what is the solution?

JW: Sleep hygiene is a good place to start. It’s like dental hygiene… good as a general baseline, but not enough if you already have a cavity.

If you do have a sleep disorder, like insomnia or sleep apnea, it’s important to get those addressed using evidence-based treatments. Like you mentioned, sleep hygiene is the placebo condition in our clinical trials… not enough to cure insomnia. What is recommended by the American Academy of Sleep Medicine as a first-line treatment is cognitive behavioral therapy for insomnia (CBT-I).

MR: A lot of people develop sleep issues for the first time as they get into midlife–which is also when many of them start to see their weight creeping up. First, Is there something physiological that occurs in midlife that affects sleep rhythms? Or have we just had longer to develop bad habits? Or more to worry about?

JW: There are physical and psychological changes. In terms of physical changes:

• We need less sleep as we age
• Our sleep tends to be more often punctuated by wakefulness, and we tend to have less deep sleep
• Hormonal changes like menopause can certainly disrupt sleep… but this should not permanently make you a bad sleeper
• More aches and pains, less physically and socially active

As for psychological changes, our expectations need to move along with the physical changes.

• We may get more anxious about sleep and health
• We may become increasingly psychologically dependent on sleep aids
• We’ve had longer to learn unhelpful things… like our brains learning that the bed is an awake place

MR: In your opinion, then, how much of an impact does midlife sleep difficulty have on midlife weight gain?

JW: This is hard to tease out because there are so many things that are changing mid-life… perhaps our activity levels, our social lives, our stress levels, our eating habits. I see this time as an opportunity to tune up health in all domains, such as learning to cook more nutritious meals now that the kids have left the house and you have more time. Or doing more self-care, taking up meditation… all good things for sleep and overall health. There’s no reason why sleep has to be bad in midlife or after.  It will change, but if you listen to your body and change with it, you can still have great sleep health.

Recommended Sleep Resources

Behavioralsleep.org

Penn CBT-I Provider Directory

American Academy of Sleep Medicine

www.jadewuphd.com

A new paper in the British Journal of Nutrition asks whether the pace at which you lose weight affects how much of that lost weight is fat (as opposed to muscle) and the impact on your metabolism after weight loss. To answer this question, the authors pooled the results of seven studies that compared rapid to gradual weight loss, where both groups lost about the same amount of weight but at different speeds.

This is a question that I am very interested in, so I was excited to find a breakdown of this new study in a recent issue of the Nutrition Examination Research Digest, a terrific publication affectionately known to subscribers as NERD.

This article also available as a podcast. Click to listen.

Advantages of slower weight loss

For years, I’ve been advocating slow weight loss as a better way to achieve sustainable weight loss, which is the only kind that really counts and the hardest to achieve.

Make smaller but more permanent changes to your habits and behavior. The weight comes off more slowly, but you aren’t just losing weight; you’re learning how to be someone who weighs less.

Part of my rationale for this approach is psychological and behavioral. To lose weight quickly, diets usually involve a dramatic but temporary change in your behavior. Once you’ve lost the weight, however, you tend to revert to old habits and behaviors that lead you to regain the weight you’ve lost.

Instead, I’d rather see you make smaller but more permanent changes to your habits and behavior. The weight comes off more slowly, but you aren’t just losing weight; you’re learning how to be someone who weighs less.

But another big part of my rationale is physiological. Many popular diets are designed to produce weight loss at a rate of 5-10% of your body weight per month. But that’s significantly faster than most people can shed body fat. If you’re losing weight faster than you can lose fat, that means you’re losing lean muscle, and that’s not what you want to be losing.

RELATED: How Fast Can You Lose Fat?

I’m convinced that slower weight loss (2% or less of your body weight per month) results in losing more body fat (and less muscle). It’s also less likely to cause a slowdown in your metabolism, which is going to make it easier to maintain the weight loss. And I’m always on the lookout for research to either support or refute this belief.

To date, there have only been a handful of studies on the advantages of slower weight loss, some of them pretty small. The latest attempts to get a better grasp on the subject by pooling the results of several studies and doing a meta-analysis of the results.

What research says about slower weight loss

Joining me to talk about the results is Gregory Lopez. He’s editor in chief of the Nutrition Examination Research Digest and Examine.com. He obtained his master’s degree in molecular biophysics from Johns Hopkins University, and his doctor of pharmacy degree from the University of Maryland, Baltimore. Greg and his team took a closer at this study in a recent issue of the Nutrition Examination Research Digest

Greg, first give us the topline: How did slow weight loss compare with fast weight loss in this meta-analysis?

Overall, their conclusion is that slow weight loss is better for body composition than fast weight loss. There are a couple of caveats based on their selection criteria. They looked at studies that had similar total amounts of weight that were lost. And so these results would not apply to people who lose more weight on one program versus another. Also, the studies were relatively short term—all less than a year.

They also looked at the resting metabolic rate. We know that when we restrict calories, eventually the body may adjust its metabolic rate downward in order to conserve energy. And that’s, of course, the bane of dieters everywhere. If we’re restricting calories more dramatically in order to lose weight more quickly,  is that having an even more deleterious effect on resting metabolic rate? What did they see in terms of resting metabolism?

The metabolic rate didn’t sink as much on a slow diet as opposed to a fast diet. Essentially, slower dieting came out on top.

Whenever we have studies comparing fast versus slow weight loss, my question is always: How fast is fast and how slow is slow? And when you and I went through the individual seven studies that they looked at, we found a really big range. The slow paces ranged from less than half a pound a week, which is pretty slow, to over two pounds a week. The fast paces ranged anywhere from one to four pounds a week.

There were a couple of studies where the slow pace was actually faster than the fast pace of one of the other studies! How does that impact what we can take away from these results?

It does muddle things. You really can’t answer the question of how much going slower or faster changes things given the analysis they did here and the data that’s available. It would have been really interesting to see an individual-level meta-analysis.

A meta-analysis takes a bunch of studies and lumps them together, and it takes the average results of these studies. So you’re taking an average of an average. If you can get the data for each individual person in the studies, you can pull them all into one single big study. And since you’d know how much exactly each person lost, rather than how much they lost on average within a study, you can do a dose-response analysis. So, if you’re interested in figuring out how slow is slow enough and how fast is too fast, that kind of analysis could be useful.

So, what we know from this particular meta-analysis is that  it looks like whether you’re losing weight faster or slower does make a difference in terms of how much fat you lose. What we can’t answer from this study is: What is the sweet spot? What is the perfect pace where most of the weight you’re losing is fat and the least is lean muscle. That is still an open question. 

I would agree with that. And I would also say that it provides a direction for future research.

I also want to talk a little bit more about the Nutrition Examination Research Digest. Tell us a little bit about what you do at Examine.com.

We try to distill the research around nutrition and supplementation—what the evidence says works and what doesn’t work. And we pride ourselves on being independent. Our goal is to kind of help people who are nutrition enthusiasts, or even professionals, get some of the latest evidence that they need.

I think you guys do such a great job—not only at going through the research but putting it into context, explaining some of the trickier concepts and pointing out potential weaknesses. I also think it’s extraordinary that you do not sell any products and don’t accept advertising. This work is completely supported by your subscription fees. That puts it pretty much in a class by itself. So, thank you for what you do, Greg, and for joining me today to add your insights. 

Digging into the Data

After my conversation with Greg, I did delve into the details of a couple of the larger studies included in the meta-analysis, where the slow pace of weight loss matched what I would recommend, to see how those folks fared.

Although both groups lost the same amount of weight, the slow group lost 10% more body fat than the faster group and 50% less lean muscle.

One of them involved 200 subjects, both men and women. Over the course of the study, the subjects lost 15% of their starting body weight on average. The slower group lost at a pace of about 1.5% of their total body weight per month. The faster group lost at a more typical rate of 4.5% of their total body weight per month. Although both groups lost the same amount of weight, the slow group lost 10% more body fat than the faster group and 50% less lean muscle.

The other study I looked at involved 68 subjects, all men. This was a shorter study and so the total amount of weight lost was less: about 6% of their starting body weight. But the pacing was virtually identical. The slower group lost 1.5% of their total body weight per month and the faster group 4.5% per month. But the difference in body composition was a lot more dramatic. The slower group lost 50% more fat and 75% less lean muscle than the faster group.

In short, slowing down the pace of weight loss does appear to offer some real advantages. For more on my approach to creating sustainable weight loss, please check out the resources at Weighless.Life.

Originally published at Quickanddirtytips.com