Always try to move your muscles before and after you eat because moving muscles helps to prevent a high rise in blood sugar after eating that can damage cells and increase your risk for diabetes, blood vessel damage, heart attacks, strokes, some types of cancers, and dementia.
Eating at night and then going to bed increases risk for obesity and diabetes by increasing hunger, decreasing calorie burning and modifying hormone and calorie balance (Cell Metabolism, Oct 4, 2022;34(10):1486-1498.E7). Eating and then resting:
• increases daytime hunger by decreasing 24-hour serum leptin (a satiety hormone), and increasing wake-time and 24-hour ghrelin:leptin hormone ratio that markedly increases hunger
• decreases wake-time energy expenditure by decreasing 24-hour body temperature and increasing markers of reduced calorie burning
• increases all the markers of increased fat storage
Changing the evening meal time of normal, non-obese men from 6:00 PM to 10:00 PM significantly increased their markers for becoming obese and developing diabetes (J Clin Endocrinol Metab, Aug 1, 2020;105(8):dgaa354). They had higher blood sugar, higher insulin, higher cortisol levels, and reduced ability to remove and use fat from their cells, These are all major risk factors for obesity. Other studies show that eating before going to bed promotes obesity and diabetes (Pharmacol Res, 2017;125(Pt B):132–141), and that eating most of your food in the morning and less in the evening helps people to lose weight (J Nutr, 2017;147(9):1722–1728).
Why Nighttime Eating is Unhealthful
Eating just before you go to bed causes high blood sugar levels and increased amounts of fat to be deposited in fat cells. Resting muscles draw almost no sugar from the bloodstream and what little they do remove from the bloodstream requires insulin (Sports Medicine, Feb 2, 2018;1-13), while contracting muscles pull large amounts of sugar from the bloodstream and don’t even need insulin to do so (Diabetes Research and Clinical Practice, Sept 2007;77(3):S87–S91).
• If you do not move around and contract your muscles after eating, you increase risk for high blood sugar levels.
• You burn the lowest amount of calories when you sleep. When you go to sleep after eating, you burn fewer calories from that food so more of it is stored as fat (Metabolism, 2009;58(7):920–926).
• Several studies show that blood sugar levels respond best to insulin during the day and worst at night (Nat Rev Endocrinol, 2019;15(2):75–89).
• Cortisol raises blood sugar levels by blocking the effects of insulin, and cortisol levels are higher when you are sleeping (Ann NY Acad Sci, 2017;1391(1):20–34).
Late-night eating is associated with blood vessel damage that increases heart attack risk (Nutrients, Feb 2022;14(3):470). A review of 129 studies found that tests for a high rise in blood sugar after meals were better than tests of fasting blood sugar levels as a predictor of coronary heart disease, strokes, or death from any cause (British Medical J, July 17, 2020;370:m2297).
My Recommendations
Eating only in the daytime and not at night significantly prolongs the lives of animals (Science, May 5, 2022;376(6598):1192-1202). The least healthful time to eat is just before you go to bed, and the most healthful times to eat are before you exercise or within an hour after you finish exercising. Exercising after eating causes contracting muscles to pull sugar from the bloodstream, which helps to prevent high rises in blood sugar. Eating within an hour after exercising also prevents a high rise in blood sugar. Your muscles can extract sugar from the bloodstream maximally without needing insulin for about an hour after you finish exercising, but this ability is then gradually lost over about 17 hours or until you contract your muscles again (J Appl Physiol, 2005;8750-7587).
