How a 72-hour fast pushes your body into ketosis

How a 72-hour fast pushes your body into ketosis

A few months ago, physical therapist Shane Foley chose to complete a 72-hour fast, putting his body into a state of ketosis. Here's what he got out of it.

Feb 22, 2023 | Shane Foley, DPT, OCS, CSCS

How a 72-hour fast pushes your body into ketosis

A 72-hour fast, or fasting for three consecutive days without any food intake, can help your body enter a state of ketosis. Ketosis is a metabolic state in which your body burns stored fat for energy instead of glucose from carbohydrates. Here are some potential benefits of a 72-hour fast that forces your body into ketosis:

Weight loss: When you're in ketosis, your body becomes more efficient at burning fat for energy, which can lead to weight loss. Fasting for 72 hours may also lead to a reduction in overall calorie intake, which can further aid in weight loss.

Improved insulin sensitivity: When you fast, your body's insulin levels decrease, which can help improve insulin sensitivity. This can be particularly beneficial for people with insulin resistance or type 2 diabetes.

Increased mental clarity: Many people report feeling more alert and focused when they're in ketosis. This is thought to be due to the fact that the brain can use ketones (produced during ketosis) as an alternative source of energy.

Reduced inflammation: Some studies suggest that ketosis can help reduce inflammation in the body. This could potentially benefit people with inflammatory conditions such as arthritis or autoimmune diseases.

Improved metabolic health: Ketosis may help improve various markers of metabolic health, such as triglyceride levels, blood pressure, and HDL (good) cholesterol levels. These benefits may also be related to the weight loss that often occurs during ketosis.

However, it is important to note that fasting with zero caloric intake for 72 hours can be challenging and should be done under medical supervision, especially if you have any underlying health conditions. Anecdotally, it was an interesting experience to realize that after the 72 hour mark, I had more energy than before, and that physical activity and exertion helped increase my energy levels, which should help force the synthesis of ketones.

For more on the benefits of fasting, check out our podcast on how fasting can help you lose weight and gain energy:

Shane Foley

Shane Foley

Shane Foley, PT, DPT, OCS, CSCS, is an orthopedic specialist who is certified in strength and conditioning, dry needling, and the Schroth Method. He is the Greenwich Site Lead.

Meet Shane