Why is it so hard to take sleep seriously? Because we don't want to believe how impactful it is on us. The thought is "why sleep for 8 hours when I can operate on 6?"
It depends on your definition of "operate." You can operate at 80% on 5-6 hours, then eventually when you've been operating at 80% for so long you don't remember what operating at 100% even feels like. At which you've established a new subjective baseline of what "normal" feels like, albeit at 20% less what it should be.
To put it not so lightly, sleep matters a lot for fat loss. These are the big reasons why.
Even with calories and *weight* loss equated. More sleep and consistent sleep/wake times produce a significantly higher reduction in adipose tissue. What this means if that even if you lose say 10 pounds, a higher percentage of that weight comes from fat as opposed to lean tissue when equating a caloric deficit.
Hormone signaling, specifically Ghrelin and Leptin often referred to as our hunger and satiety hormones, respectively. When your body is sleep-deprived, it produces higher levels of Ghrelin (hunger hormone), while levels of Leptin decrease, providing an increased response in hunger. Sleep and calories are our bodies primary fueling and recovery capacities. As one becomes less available, demand on the other increases. This works against you when you're already in a deficit intentionally making the backup source less available.
Sleep deprivation significantly reduces insulin sensitivity. This is related to bullet point 1. You want to be insulin SENSITIVE, this is fantastic for metabolic flexibility and makes it easier for you to lose fat. Also allows you to eat more carbs while staying leaner and who doesn't want that. Again, equating calories and adherence, being more insulin sensitive yields better fat loss results.
It's important to note that I'm not talking about severe sleep restriction either. Simply comparing 5-6 hours per night to 8+ hours per night. What is most fascinating to me is sleep is one of those rare mega impact areas. Even keeping calories/training/macros/adherence untouched...improve sleep and you simply produce better results.
Here is my starting approach for improving your sleep routine.
1️⃣ Set consistent sleep/wake times and try to hold yourself to it. Especially consistent wake times.
2️⃣ Reduce screen time as the sun goes down, or use blue light blocking glasses when working after dark. Especially the later it gets.
3️⃣ Unwind, slow down, and incorporate stress relieving activities before bed. Slow your brain down. My favorite way to do this is to read before bed. (Nothing too engaging/exciting though!)
4️⃣ Make the room colder. Somewhere around 65 degrees will make for the best sleep. Colder than you'd think, right?
5️⃣ Drink some hot "sleep tea." Passionflower and Valerian Root help to influence levels of GABA in our brain which is involved with relaxing and inducing sleep. Yogi's Bedtime Tea and Celestial Seasonings Sleepytime Extra are my two top picks.