Evidence for time-restricted eating in humans — heart health and improved biomarkers | Satchin Panda
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Evidence gathered from a meta-analysis of multiple studies indicates that time-restricted eating is beneficial for cardiovascular health in humans. Recent data from animal studies indicate that time-restricted feeding – even in overweight animals eating a poor diet – has beneficial effects on metabolic health. Studies investigating whether the same benefits will be observed in a real-world setting in humans are lacking, however. In this clip, Dr. Satchin Panda describes the state of the science with regard to understanding the beneficial effects of time-restricted eating in humans.
- Rhonda: So just sort of since we're talking about this, do we have any human evidence that the people that have, for example, like metabolic syndrome, if they eat within a time-restricted eating window, there's any benefits to that without changing their food composition?
- Satchin: Well, historically most of these research studies haven't looked at timing per se, but there was a very nice, comprehensive review published by American Heart Association that went back to many studies where timing, or at least how many times people ate during the day, was recorded. And after compiling all the studies, it was close to 70 or 80 different studies related to fasting of decent quality, how many times people ate, that found that, yes, limiting food to a certain number of hours during the day or maintaining overnight fasting was beneficial for cardiovascular health. So that's a very well done meta-review of existing literature. What we need to do now is to look for new studies where this is specifically looked at where everything else is kept constant and timing is changed so that we'll see whether the benefit is seen among individuals who already have metabolic syndrome. So that's what is lacking in the field. And, as you know, this is a very new area of research and NIH funding cycle is five years, so any of the studies will take at least five to seven years before we see any result and peer-reviewed journals.
- Rhonda: Particular for, I guess, a clinical trial of actually looking at someone with metabolic syndrome. Probably obesity... I mean if a person is obese, it may take a little more than just time-restricted eating to lose weight. Although they may, they may lose some. They may require more of a, like, prolonged sort of fasting, but the time-restricted eating certainly would affect their... I would predict would affect their metabolism.
- Satchin: Yeah. So what we see in our study, a small study that was published, and also some of the other studies that may be in the pipeline, when people adopt a time-restricted feeding paradigm in their regular life, in real life, not in the laboratory condition or in clinical trial, then they naturally reduce their caloric intake without even counting calories. So, for example, when they stop, suppose their target to stop around 6:00, 7:00, or 8:00 in the evening, then the late night snacks and then the late night glass of wine or beer that used to be their usual habit, they stop that. So in that way they're doing two things, one is reducing calories and also improving nutrition quality because that extra energy-dense diet is not getting into their system. So in that way I'm hopeful that we'll see some weight loss, and then some improvement in real health, blood biomarkers. And in rodent studies what we have seen when we take already fat mice, who have been eating a really unhealthy diet for a long period in their life, and then put them on a time-restricted feeding paradigm, they don't become, like, lean mice in terms of body weight. They become overweight, not normal. But surprisingly they're biochemically...or physiologically they're more healthy because their blood biomarkers for glucose, cholesterol, triglycerides, they come back to almost normal range. So we have to make the distinction that some people may not lose a huge amount of weight, but they might actually see benefits in their metabolism and physiology. So that's one thing you have to look out for.
- Rhonda: But this is, the mouse study you were just referring to, they were still fed a poor diet?
- Satchin: Isocaloric.
- Rhonda: Yeah, okay.
- Satchin: Yeah, they were still fed a poor diet, isocaloric diet.
- Rhonda: So imagine if they were fed a better diet and...the obese mice were fed a better diet and they were doing time-restricted eating.
- Satchin: Yeah, so they would be much better.
- Rhonda: Much better.
- Satchin: They would lose more fat mass and become much more healthier.
A measurable substance in an organism that is indicative of some phenomenon such as disease, infection, or environmental exposure.
A large class of diseases that involve the heart or blood vessels, including stroke, hypertension, thrombosis, heart failure, atherosclerosis, and more. Cardiovascular disease is often caused by lifestyle factors. As such, up to 90 percent of cardiovascular disease may be preventable.[1]
A waxy lipid produced primarily in the liver and intestines. Cholesterol can be synthesized endogenously and is present in all the body's cells, where it participates in many physiological functions, including fat metabolism, hormone production, vitamin D synthesis, and cell membrane integrity. Dietary sources of cholesterol include egg yolks, meat, and cheese.
A cluster of at least three of five of the following medical conditions: abdominal (central) obesity, elevated blood pressure, elevated fasting plasma glucose, high serum triglycerides, and low high-density lipoprotein (HDL) levels. Some studies estimate the prevalence in the USA to be 34 percent of the adult population. Metabolic syndrome is associated with the risk of developing cardiovascular disease and diabetes.
The thousands of biochemical processes that run all of the various cellular processes that produce energy. Since energy generation is so fundamental to all other processes, in some cases the word metabolism may refer more broadly to the sum of all chemical reactions in the cell.
Restricting the timing of food intake to certain hours of the day (typically within an 8- to 12-hour time window that begins with the first food or non-water drink) without an overt attempt to reduce caloric intake. TRE is a type of intermittent fasting. It may trigger some beneficial health effects, such as reduced fat mass, increased lean muscle mass, reduced inflammation, improved heart function with age, increased mitochondrial volume, ketone body production, improved repair processes, and aerobic endurance improvements. Some of these effects still need to be replicated in human trials.
A molecule composed of a glycerol molecule bound to three fatty acids. Triglycerides are the primary component of very-low-density lipoproteins (VLDL). They serve as a source of energy. Triglycerides are metabolized in the intestine, absorbed by intestinal cells, and combined with cholesterol and proteins to form chylomicrons, which are transported in lymph to the bloodstream.
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