Fat, Mental Performance & Sleep Deprivation
Sleep deprived people will eat extra calories the following day
TWO things you need to know this week.
Total fat storage can decrease your mental performance.
Why sleep deprivation can lead to increases in fat storage.
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Neuro Athletes,
I'm writing this email from the epicenter of the country — Miami! I came down here to give a talk at ISVA (international sports vision association) on Friday and I only landed here 24 hours ago after travelling from Australia. So the one thing on my mind right now is recovery. I plan to sleep, get my circadian rhythm back on est and spend some much needed time in the sauna and ice bath!
Last week in a podcast with Dr. Andy Galpin I mentioned that fat mass is a contributing factor to longevity, performance and cognition. You can listen to it by clicking here.
When working with most of my clients I tend not to dip into the buckets that I am not trained in, that is nutrition. However, I do get the occasional “Louisa, how can I reduce my fat so I can be a better athlete” and I think that’s where we are going wrong with the ‘fat’ conversation. I don’t think we understand how fat is a contributing factor is cognitive performance as well.
There is not much controversy that obesity has neurologic consequences. The physiology of the normal human energy system, and how it becomes impaired in obesity and can lead to cognitive impairments, is complicated and multifactorial.
There’s numerous studies demonstrating that elevated adiposity was associated with larger global switch costs on the task-switching paradigm in women and men indicating that elevated adiposity is associated with worse performance on some aspects of cognitive control in young adults.
Alongside diet and exercise, sleep — another important yet often neglected lifestyle — can also affect weight loss. Specifically, research has linked short sleep duration (<7 hours) with higher body fat and increased risk of obesity and higher sleep duration (>9 hours) with lower lean mass.
As mentioned above, I will stick to my lane in this newsletter by offering an approach to fat loss that not many deem to take — the sleep route.
Primer:
Neural circuits involved in energy balance and peripheral homeostasis signaling, including nutritional status, are complex.
Figure. Regulation of energy balance and homeostasis depends on both energy intake and expenditure. Reward circuits (green) activate executive cortical function, which in turn activates the autonomic pathways in the brainstem stimulating physical activity. This neural activity is modulated by signals from the periphery, ghrelin, released by the stomach, and leptin, released from energy stores.
A simple overview is provided here that focuses on energy expenditure, assessed in terms of resting energy expenditure, the thermogenic effect of food, and the energy expenditure from physical activity. Some energy expenditure is voluntary, for example, the decision to engage in physical activity. Other energy expenditure is involuntary, such as autonomically controlled thermogenesis in brown adipose tissue (BAT), which modulates resting energy expenditure, thermic effect of food, and possible energy expenditure during activity.
Sleep Duration And Fat Loss
To explore the link between sleep duration and fat loss, one study observed subjects on a calorie deficit for 24-weeks and found a positive correlation between sleep hours and fat mass loss (Figure 1). According to the authors, every additional one hour of sleep decreases 0.7 kg in fat mass.
A positive correlation between sleep duration and body fat loss. Obesity Facts.
Similarly, in a study involving 14 days of caloric restriction, participants lost more fat mass (56% vs. 25%) and less muscle mass (60% lesser) when they slept for 8.5 hours compared to 5.5 hours per day.
Incorporating a longer duration of intervention and sleep patterns in real life, another study put 36 overweight/obese adults on a calorie deficit for eight weeks. In addition, one group slept one hour less than usual on weekdays while the other slept their usual hours. Although both groups lost similar amounts of weight, fat mass loss was significantly higher (82.7% vs. 58.4%) in the group with unchanged sleep duration.
Of note, these studies mainly involved sedentary overweight/obese subjects who were on a calorie deficit, which rules out the general population who are physically active, lean, and on a balanced energy diet.
Nevertheless, while there is no direct evidence to support this correlation for the latter population, other relevant studies have shown indirect evidence supporting the positive influence of sleep on fat loss.
Sleep Duration And Appetite Hormones
A study explored the effect of sleep restriction on appetite hormones (i.e., leptin, which promotes satiety, and ghrelin, which stimulates hunger) in healthy men with healthy body weight. They found that,
Leptin levels were lower in individuals after two days of 4-hour sleep but higher after two days of 10-hour sleep (Figure 2).
In contrast, ghrelin level was higher in individuals after two days of 4-hour sleep than after two days of 10-hour sleep. These resulted in greater self-reported hunger and appetite ratings, which may encourage excess eating and thus, hinder fat loss.
Figure 2: Differences in leptin and ghrelin levels after two nights of short or long sleep duration. Annals of Internal Medicine.
Sleep Architecture, Appetite, And Energy Metabolism
Studies that assess sleep architecture in addition to sleep duration and quality — which was excluded in the previous studies — have shown that individuals with decreased slow-wave sleep (SWS) or rapid-eye-movement (REM) sleep phases tend to be hungrier. Furthermore, sleep fragmentation, which reflects poor quality sleep, appears to encourage the body to use carbohydrates rather than fats for energy, which may predispose to overweight.
Overall, despite the limitations and scarcity of direct evidence on the influence of sleep on fat loss, numerous studies have presented indirect evidence supporting the positive impact of sleep on weight management. In particular, quality sleep — with regards to sleep architecture — proved to be a crucial factor supporting the progress of an ideal weight loss. While the link between sleep duration and body weight composition seems vague, getting the recommended 7 to 9 hours of sleep can, at least, increase the chances of getting quality sleep.
That’s it for this week! I really hope you enjoyed this newsletter, if you did please feel free to comment or share this along to someone who you think could benefit.
Until next time,
Louisa x
This Week On The Neuro Experience Podcast
Doug Evans is joining us today to speak about the powerful effects of sprouting. This conversation opened my eyes to the possibilities of sprouts. This compound is present in all cruciferous vegetables. In animal studies, when glucoraphanin is chewed or swallowed, it produces a cancer-protective compound SULFORAPHANE. This sulforaphane absorbs toxins from the body and flushes them out through urine.
The best way to get sulforaphane is to sprout your broccoli organic seeds in your own home. At between five and six days old, the sulforaphane in broccoli sprout contains up to 100 times more than in mature plant. The sprouts can also be used in smoothies, sandwiches, wraps or salad apart from juicing.
Broccoli sprouts are now readily available in major retail stores, but make sure you buy organic, non-GMO, or better still buy the seeds and sprout at home.