Dr. Marie-Pierre St-Onge's research reveals a sex-specific hormonal response to short sleep. Men experience a rise in ghrelin (hunger hormone), while women see a drop in the satiety peptide GLP-1, explaining different drivers for overeating when tired.
In a lab study with a controlled diet, participants undergoing severe sleep restriction (4 hours/night) showed no change in cortisol, glucose, or insulin. This suggests that external life stressors, not just sleep loss itself, may be required to trigger metabolic dysregulation.
While severe, short-term sleep loss in a lab didn't alter metabolic markers, a six-week study found reducing sleep by 90 minutes per night in a normal environment increased insulin resistance and blood pressure, highlighting the danger of chronic, moderate sleep debt.
A controlled study revealed that specific nutrients directly impact sleep architecture. Higher fiber intake was associated with more deep (slow-wave) sleep. Conversely, higher saturated fat intake led to less deep sleep, and simple sugars caused more sleep arousals.
In a lab setting, when participants were allowed to choose their own meals, their time to fall asleep increased by over 70% and their deep sleep decreased by about 20% compared to when they ate a controlled, balanced diet provided by researchers.
The popular belief that pre-midnight sleep is inherently more valuable is not supported by data. Feeling less rested from sleeping late is likely due to desynchronization with your personal circadian rhythm, not because those specific hours hold superior restorative power.
A study using a metabolic chamber found that identical meals consumed later in the day led to lower fat oxidation. This suggests that meal timing, independent of caloric content, significantly impacts whether your body burns or stores fat.
Research showed that drinking ginger powder dissolved in hot water significantly elevated the thermic effect of food. This simple dietary addition can boost energy expenditure after a meal, potentially by activating the capsaicin receptor pathway.
Women's bodies show a more sensitive metabolic response to sleep disruption. For example, their blood pressure is more likely to increase at lower severities of sleep apnea compared to men, highlighting a crucial sex difference in sleep-related health risks.
A study found that participants on a weight loss diet who used MCT oil lost more weight than those using olive oil. MCTs are processed differently, traveling directly to the liver to be burned for energy, which increases the thermic effect of food.
In an industry-funded study, participants who replaced their typical low-fat or high-saturated-fat snacks with corn chips (like Doritos) showed improved cardiometabolic risk factors, including a better lipid profile, attributed to the corn oil's polyunsaturated fat content.