FoundMyFitness Podcast Summary | Dr. Rhonda Patrick | Dr. Satchin Panda on Time-Restricted Feeding and Its Effects on Obesity, Muscle Mass and Heart Health (Part 4)

47:50 – Time restricted feeding and intermittent fasting. The commonality is the prolonged period of fasting (prolonged meaning 6-8 hours because that is how long it takes for glycosine to deplete and we begin to use fat for energy; at 8-10 hours ketone bodies are produced). Ketone bodies are are used as energy for a diverse array of cell types, including neurons. When we eat we are using glucose and in this process we create reactive oxygen species. These reactive oxygen species can damage DNA and lipids nearby. We have repair mechanisms and, for reasons we don’t understand, fasting activates these mechanisms. In a fasting state, the body can no longer rely on food from the environment; the body makes energy through gluconeogenesis, fat oxidation, and ketone bodies.

In intermittent fasting, there are caloric restriction. There are no caloric restrictions in time restricted eating. Caloric restricted eating (restricting calories by 30%) has been shown to increase the lifespan of worms, flies, mice, dogs and monkeys. This is how the two forms of fasting are different.

51:30 – Fasting ingrained in evolution. Hunter-gatherers would go about finding food in the day time. More so, animals on the savanna are most active between the morning and twilight; thus it would seem best to optimize the human body so that it is ready to obtain its meal. Time restricted feeding attempts to incorporate this natural primordial physiology.

56:26 – Recently, it has been discovered that melatonin receptors are present in pancreatic beta islet cells. When melatonin engages with these receptors, it inhibits the insulin secretion. This explains why we are less insulin sensitive during the night.

59:20 – Human trials via Dr. Panda’s app. The studies were inconclusive in answering the question of how does time restriction alone effect the body. It is inconclusive because people who participating in time restriction, unknowingly or knowingly limited their caloric consumption as well. Subjects in the study claimed to sleep better at night and were more energetic in the morning.

1:05:43 – Dr. Panda’s website:

1:08:43 – If we can capture what, when and how much people eat sleep and move around, then we have a nearly complete picture of someone’s lifestyle. This will be highly useful for research, care physicians, and public health.

1:14:00 – Heart disease. A lot of things regulate our likelihood of dying from heart disease. Dr. Panda’s research has looked into how time restricted feeding affects the heart. Some fruit flies were given food for twelve hours and others were given food for twenty four. It was shown that the group that was restricted did not develop arrhythmia of the heart as fast as the other group.

1:17:37 – Heart rate variability. HRV was improved when the fruit flies were time restricted. There are a few theories as to why this was. It is theorized that mitochondria were healthier in the sense that they were not producing as much reactive oxygen species. They looked at the gene expressions of flies on the time restricted eating regiment and found that the genes responsible for the electron transport chain were inactive. This implies that maybe they have fewer reactive oxygen species or reduction of the use of the electron transport chain is beneficial. 

The other theory as to why heart rate variability is improved involves proteostasis (the biogenesis, folding, trafficking and degradation of proteins within and outside of the cell). Problems with protein folding can be a signal for heart problems; the processes at work were executed better when feeding was time-restricted.

1:20:50 – The gut. Bacteria is also an a circadian rhythm. Some species of bacteria are more abundant at different times of the day. This balance was different in obese animals versus non obese animals. When we eat in a time restricted environment, we have fixed intervals of fasting and eating. During eating, a set of bacteria will bloom in numbers and a different set will become quiescent. After a few hours of fasting, the roles are reversed. This ebb and flow of bacterial species nurtures other species and they cohabit our gut. We need different “players” to do different things throughout day and night. The alternation of plenty food and a certain pH and lack of food and a different pH promotes diversity that for reasons we don’t understand is much better for us. Diversity in the gut is very important.

1:24:48 – Bile acid. Bile acids are better managed with time restricted feeding. It is made in the liver and is cycled in between the liver and the gut. Bile acid is made from cholesterol. There are enzymes in the liver that are up regulated in time restricted eating which turn cholesterol into bile. The bile acid goes to the gut and helps get fat into the gut. This is apparently a benefit.


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