Part of an ongoing series on how to use supplement and behavior-based plans to treat common maladies. To read the detailed supplement plans, order supplements, or download the patient resource sheets, go here to create a free patient account at Fullscript by entering your name and email address: Dr. Mark McDonald’s Fullscript dispensary


Fasting has long been promoted as a weight-loss tool, but evidence now shows the practice not only sheds pounds but also improves mood and sleep quality.

King’s College London published a study that included nearly 40,000 participants who benefited in surprising ways from intermittent fasting, which is the practice of restricting eating to a narrow window (anywhere from one to eight hours). The most popular form is 16:8 or 16 hours of fasting followed by eight hours of eating (not continuously!). The college found that intermittent fasting was a more potent method of weight loss than restricting calories. Benefits, though, went beyond weight loss and what follows from it (reductions in waist circumference, body fat percentage, visceral fat, blood pressure, and glycated hemoglobin).

Study participants who practiced intermittent fasting also slowed improvements in sleep quality, energy, and mood.

Restricting eating to just two meals a day (generally by eliminating breakfast and late-night snacks), then, brings psychological benefits as well. Although shorter eating windows did show somewhat greater benefits than longer ones, the most important factor in determining results wasn’t the size of the eating window but rather the consistency of practice. Regardless of the window, those who remained disciplined in observing the fasting routine every day showed significantly greater results than those who “cheated.” Similar to exercise, it’s the consistency of effort rather than size of effort that matters.

Given the rising popularity of GLP-1 “weight loss’ drugs like Wegovy and Ozempic, linked with gastrointestinal paralysis, thyroid cancer, alopecia, and suicidal ideation by the FDA, we should be more focused on safe, inexpensive, and universally accessible ways to improve metabolic health.

Intermittent fasting is an excellent tool for anyone trying to lose weight, without the accompanying dangers of pharmaceutical products. If intermittent fasting also helps with sleep and mood, perhaps we should all give it a try. We have nothing to lose and a lot to gain.

At the very least, you’ll no longer need to spend time making breakfast, and you’ll save money on snacks.

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