“I’m not fat, I’m just really leptin resistant!” said the insomniac at the buffet line.

What are Leptin and Ghrelin hormones, and how do they interact with the body?

Let’s start with Leptin hormones, Leptin is a adipocyte-derived hormone that suppresses appetite, it’s a mediator of long-term regulation of energy balance acts as a food intake suppression agent, it comes on slowly to gradually bring the body into a state of fullness, if it was fast acting you would eat and immediately feel full too quickly before you had consumed a proper amount of food to sustain yourself.

Ghrelin is a predominantly stomach-derived peptide that stimulates appetite, it comes on fast and strong to initiate food intake, and is the source of your feeling just fine one hour and then “starving” the next.

In a proper cycle these hormones regulate your intake, motivate you to find food and satisfy you in time not to eat yourself to death, the real problem comes in when you entertain additional factors like sleep.

1,024 volunteers from the Wisconsin Sleep Cohort Study, a population-based longitudinal study of sleep disorders. Participants underwent nocturnal polysomnography and reported on their sleep habits through questionnaires and sleep diaries. Following polysomnography, morning, fasted blood samples were evaluated for serum leptin and ghrelin (two key opposing hormones in appetite regulation), adiponectin, insulin, glucose, and lipid profile. Relationships among these measures, BMI, and sleep duration (habitual and immediately prior to blood sampling) were examined using multiple variable regressions with control for confounding factors.
A U-shaped curvilinear association between sleep duration and BMI was observed. In persons sleeping less than 8 h (74.4% of the sample), increased BMI was proportional to decreased sleep. Short sleep was associated with low leptin (p for slope = 0.01), with a predicted 15.5% lower leptin for habitual sleep of 5 h versus 8 h, and high ghrelin (p for slope = 0.008), with a predicted 14.9% higher ghrelin for nocturnal (polysomnographic) sleep of 5 h versus 8 h, independent of BMI.

What this means: Short sleep (sub 8 hours) seems to negatively impact your future Leptin levels, which contributes to over eating.