If you’re interested in fitness and weight loss and you’ve been following the trends at all, then you probably have heard of intermittent fasting.
Intermittent fasting means alternating between fasting and eating for longer periods than just while you’re asleep (which is what most of us do). The most common patterns are just skipping breakfast and eating a late dinner (16-17 hour fasting), and fasting for a full 24 hours once or twice per week.
Here’s the concept behind it.
Health Benefits of Fasting in General
I wrote here on the health benefits of longer fasts, and the fact that studies show it helps to regenerate the immune system. Specifically, fasting lets your body “clean house,” getting rid of damaged cells.
This comprehensive study indicates that in animal studies, calorie restriction or alternate day fasting lowers the incidence of cancer and heart disease. (This is likely because fasting puts you into a state of burning fat rather than sugar, and both diseases thrive on sugar.)
No doubt about it, fasting from time to time (no matter how you do it) is good for most people. There are exceptions: i.e. if you’re hypoglycemic (though this is usually secondary to something else—so get the problem fixed before you try this), or if you’re already very weak and depleted.
Fasting = A Low Insulin State
When you eat, your body converts the carbs you consume into glucose (sugar). Glucose triggers the release of insulin from your pancreas, and then the glucose in your bloodstream rushes into your cells. If you ate a meal comprised entirely of sugar or simple carbs, this spike and crash is quite dramatic, and it leads to hypoglycemia and the intense need to eat again, to eat quickly, and to eat more sugar and carbs to get your glucose back up.
If you’re eating a more balanced meal, the rise in blood glucose will be more gradual, and so the corresponding rise of insulin will be more gradual as well. This is definitely healthier, but it will mean that your body has a steady supply of glucose throughout the day and doesn’t have to resort to alternative energy sources, like fat.
When fasting, though, your body obviously isn’t getting any glucose from your food, so it has to pull its energy from storage instead. Also, bonus: on the other side of a fast, your body’s sensitivity to insulin improves, enabling you to use the glucose you do consume more efficiently.
But What about Breakfast?
I admit, I often tell patients to eat a high protein breakfast within 30 minutes of waking, and then to eat six small protein-containing meals per day. The best patients to follow this advice for weight loss are those in early stage adrenal fatigue, because it helps to minimize the output of cortisol (which mobilizes sugar from the liver in between meals, and can be a cause for high blood sugar and weight gain, despite a good diet).
That said… for patients with insulin resistance and a weight problem but no adrenal issues, intermittent fasting is a great idea for weight loss. Periodic fasting (however you do it) is certainly a great idea for overall health!