Life in the “Fast” Lane?

Types of Fasting

The Idea

When our cells are stimulated by a steady stream of fuel (food), they process glucose, a form of sugar that our bodies can convert into energy. However, when we fast, our bodies do not have their usual access to glucose, forcing the cells to use other ways to produce energy.

Sometimes considered unhealthy, short-term fasting can offer excellent health benefits. As research grows in this area, fasting is becoming more widely accepted as a legitimate way to manage weight and prevent disease. However, it is important that fasting is done in proper and healthy ways.

The Science

Science Behind Fasting

Basically, fasting cleanses our body of toxins and forces cells to perform in ways other than when we eat the usual three meals a day.

When we fast, the body begins gluconeogenesis, a natural process of producing its own sugar. The liver helps by converting non-carbohydrate materials like lactate, amino acids, and fats into glucose energy. Because our bodies conserve energy during fasting, the amount of energy our bodies burn while resting becomes more efficient, which lowers our heart rate and blood pressure.

Ketosis, another process that occurs later into the fast cycle, happens when the body burns stored fat as its primary power source. This is the ideal mode for weight loss and balancing blood sugar levels.

Fasting puts the body under mild stress, which makes our cells adapt by enhancing their ability to cope. In other words, they become stronger. Think about what happens when we put our muscles and cardiovascular system under stress during exercise. As with exercise, we need adequate time to rest and recover. That’s why short-term fasting is recommended.

The Types

In lab studies, these three types of fasting have shown positive effects on health and longevity:

  • Time-Restricted Feeding
    This is the process of limiting calorie intake to a specific timeframe that aligns with our circadian rhythm – our “body clock” that tells us when to sleep, rise, eat, and more. Eating meals only during an 8-to-12-hour period each day, while fasting from 10 a.m. to 6 p.m., for instance, aligns with our circadian rhythm. Body systems work better when synchronized with one another. Late night snacking when our body should be sleeping throws our natural repair system out of sync. This also gives our bodies more time to repair, which is healthier.

  • Intermittent Calorie Restriction
    This simply means reducing the number of calories consumed in a day. Research has focused on a two-day diet where calories are reduced in half and carbohydrates are limited for two consecutive days in a week. This approach puts the body through short and intensive therapy. The intermittent calorie restriction approach also reminds us that we do not need to consume constantly. Then, when we do eat, we can choose wisely and continue everyday activities and exercise with reduced fuel.

  • Periodic Fasting That Mimics Diets
    This means limiting calorie intake for three to five days, prompting the cells to deplete glycogen stores and begin ketosis. You can do this without eating food, but it isn’t considered the safest option. A specific five-day calorie-limited diet (around 1,000 calories per day) is enough to mimic fasting without depleting nutrients. It is thought that this method is better than the two-day fast because it allows the body to enter ketosis and begin a true cleanse.

Health Benefits of Fasting

Admittedly, fasting can be challenging and sometimes uncomfortable, but it has been shown to:

  • Boost cognitive performance

  • Protect from obesity and associated chronic diseases

  • Reduce inflammation

  • Improve overall fitness

  • Support weight loss

  • Decrease the risk of metabolic diseases

  • Benefit cancer patients

Fasting during chemotherapy jump-starts the immune system and exposes the cancer cells. Ridding the body of old, toxic cells and replacing with new, healthy ones may be just the answer. Traditionally, cancer patients are told to increase nutrients and caloric intake while undergoing chemotherapy treatments, but this approach is now under review.


Please note: If you are interested in fasting, please consult a physician first.

Paul Gravette