Intermittent Fasting

Posted: 19 June 2018

Many who go on diets achieve weight-loss, whether it is 2kg or 20kg. What most people don’t achieve is sustaining their desired weight for the long-term. Diets are designed for rapid results. However they are not designed for sustainable long-term results. What is required is a long-term approach. This leads us onto intermittent fasting and the health benefits associated to this way of approaching food, health and nutrition.

First of all what is Intermittent Fasting?

Intermittent fasting (IF) is essentially an eating pattern that cycles between periods of fasting and eating. There are no recommendations about which foods you should eat, the importance is placed on the timing of food and quantity.

What are the benefits of intermittent fasting?

Fasting eating patterns have been seen to extend lifespan and increase resistance to age-related diseases in rodents and monkeys. It has also been shown to improve the health of humans through decreasing oxidative damage caused by the presence of free radicals due to the reduction in energy intake, causing fewer free radicals to be produced in the mitochondria of cells and therefore less oxidative damage to the cells (side note: antioxidants eradicate free radicals with foods high in antioxidants being great for our health. Foods high in antioxidants include; goji berries, wild blueberries, dark chocolate, pecans, kidney beans)

Fasting also improves our cells ability to respond to environmental stressors, including extremes of temperature, exposure to toxins, and mechanical damage. Recent findings suggest that some of the beneficial effects of fasting on both the cardiovascular system and the brain are caused by brain-derived nervous tissue growth in the brain. Interestingly, cellular and molecular effects of fasting and caloric restriction on the cardiovascular system and the brain are similar to those of regular physical exercise, suggesting shared mechanisms.

Fasting has also been shown to improve insulin sensitivity that results in reduced plasma glucose and insulin concentrations and improved glucose tolerance, which is great news for all particularly those with diabetes. This is believed to be caused by improved dilation of blood vessels in obese humans, which is associated with an apparent increase in insulin sensitivity, suggesting a role for improved glucose breakdown.

How to approach a fasting eating pattern?

In a study of overweight human subjects, it was shown that a one -meal-per-day diet (with reduced calories) significantly improved left ventricular function and recovery of BP and HR following exercise. That sounds great but is not practical for the long-term. Here are a few suggestions;

  • The 16/8 Method: skipping breakfast or dinner and restricting your daily eating period to 8 hours, for example from 1 pm to 9 pm. Then you “fast” for 16 hours in between.
  • Eat-Stop-Eat: fasting for 24 hours, once or twice a week, for example by not eating from dinner one day until dinner the next day.
  • The 5:2 Diet: On two non-consecutive days of the week, only eat 500-600 calories. Eat normally the other 5 days.

Through consumption of fewer calories, fasting and caloric restriction will lead to weight-loss as long as there is not over compensation during eating periods and any of the above methods will achieve this.

Supporting Material

Caviezel F, Margonato A, Slaviero G, Bonetti F, Vicedomini G, Cattaneo AG, et al. (1986) Early improvement of left ventricular function during caloric restriction in obesity.

Jacob A. Panici, James M. Harper, Richard A. Miller, Andrzej Bartke, Adam Spong, and Michal M. Masternak,(2010), Early life growth hormone treatment shortens longevity and decreases cellular stress resistance in long-lived mutant mice