The only proven way of currently extending life expectancy in a variety of mammals is undernourishment (not malnourishment) but requires further study to see whether it has undesirable side effects.
Long lived species have less response to famine so, according to Aubrey de Grey, not likely to have a big impact in humans.
More info: CR Society International
Low-calorie diet prevents age-related molecular changes – Medical Xpress – 25-May-2018
Epigenetic changes strongly influence the way the genes operate.
Methylation in humans changes in different areas with age.
Harvard Medical School studied methylation in mice as they aged.
Changes become more evident at an older age.
Long-term low-calorie diet displayed slower age-related changes.
Short-term cuts in calories instead made them even faster.
CR Leads to Longer Life but Less Grey Matter – Geneng News – 5-Apr-2018
New study shows caloric restriction in lemurs extended lifespan up to 50%.
Grey mouse lemur is a small primate with a lifespan of around 12 years.
Fed 30% fewer calories from early adulthood lifespan up by almost 50%.
Brain imaging showed a slight loss of grey matter (neuronal cell bodies).
However, cognitive and behavioral performances were not modulated.
Reduced-calorie diet slows ageing in people – Nature – 22-Mar-2018
CALERIE multi-centre trial tested 200 healthy, non-obese adults over 2 years.
State-of-the-art metabolic chambers measure oxygen use and CO2 exhalation.
Reducing calorie intake by 15% mapped to more energy efficient sleeping.
Other clinical measurements were in line with reduced metabolic rate.
Evidence that results in other animals can be applied to ourselves.
CR improves intestinal-tissue regeneration after injury – News Medical – 22-Feb-2018
Research pinpoints the cell responsible for improved regenerative abilities in the intestines.
Reserve stem cells, can survive radiation and quickly rebuild intestinal tissues.
Mice fed 60 percent of normal calories expanded reserve intestinal stem cells five-fold.
These cells also seemed to divide less frequently.
Mechanism Behind Calorie Restriction and Lengthened Lifespan Uncovered – Temple Health – 14-Sep-2017
Epigenetic drift occurs more rapidly in monkeys than in humans.
Chemical modifications such as DNA methylation control mammalian genes.
Methylation patterns drift steadily throughout life.
Examinined blood collected at different ages from mice, monkeys and humans.
The greater the amount of epigenetic change the shorter the species’ lifespan.
Calorie restriction extends life of monkeys by 3 years – New Scientist – 17-Jan-2017
Trial in macaques has found that CR makes them live 3 years longer than normal – equivalent to 9 years in people.
There were also lower rates of heart disease and cancer.
About 10% life extension compared to 50% seen in mice.
Eating less may lead to longer life – Irish Times – 7-Apr-2016
Greater longevity for those who reduce their calorie intake.
Calorific restriction has been shown to extend lifespan in some species.
Professor Steven Austad of the University of Alabama at Birmingham says studies on members of the Calorie Restriction Society show they have reduced cardiovascular risk.
COMMENT: so maybe not extending maximum lifespan, just increase average life expectancy by not dying early of a heart attack?
Review of Mechanisms that Slow Aging from Calorie Restriction – Fight Aging! – 6-Jan-2015
CR changes near everything in the operation of metabolism and slows near every measure of aging making it difficult to figure out chains of cause and effect.
Does not repair of damage.
Review of recent studies includes:
Mitochondrial activity and ROS production are modulated by CR
Importance of membrane lipid composition on the CR effect
Antioxidant activities in ageing and CR
AMP-dependent protein kinase (AMPK)
… and many more.