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David Fisher, 61 years old, is one of the few long term adherents to calorie restriction in the world. While most people only stick to a diet for just a few weeks or months at a time, he has managed to maintain a strict CR diet for 30 years!

In 2004, he was featured in the Guardian, where he explained how he came across the diet, why he began restricting his calories, and he gave some information about his diet at the time.

Then in 2009, Dave took part in a series of interviews in newspapers such as The Independent, Daily Mail, and was also interviewed for TV programs about CR, intermittent fasting, and life extension.

A few years later (2012) he took part in a short TV interview about his CR diet, which you can see below.

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After these interviews, Dave had mostly disappeared and never did any follow-up interviews. But due to hundreds of questions that I’ve received about him and people asking me if there were any updates, I thought I’d reach out for an interview, and he kindly agreed!

But first of all, for those who have not been involved in the CR Society email lists, CR forums, or life extension community, here’s a bit about his popular TV appearances.





Dave Fisher’s TV appearances about his CR diet and longevity

Two of the TV appearances that Dave took part in were with Dr. Michael Mosley, who is a well-known doctor, BBC presenter, and journalist in the UK. He is also now famous for his 5:2 diet, which has become a popular way to practice intermittent fasting.

In these shows, Dave and Michael competed in a series of tests to see who was biologically younger. Michael had been on a typical western diet all his life, while Dave had been practicing CR for many years.

As you might expect, the benefits of practicing CR were clear when they compared their results and biological age against each other.

Dave was obviously much leaner on the diet with just 7% body fat compared to 21% for Michael.

When they measured lung capacity – which decreases with age – Dave also did much better, indicating that he was in better physical health than Michael.

Dave also had a more favorable diseases risk profile than Michael, with an extremely low risk of diabetes, heart disease, and stroke. Calorie restriction is very powerful at protecting humans against these leading killers that affect most people in the west.

And the benefits of CR are not just on the inside either! Calorie restriction might also help you look younger for longer by slowing down skin aging.

In fact, Dave and Michael met with cosmetic surgeon Mr. Prakash, and when Michael asked if he could guess their ages, he said that Michael was probably 51 and Dave was 35 years old (both are only months apart in age). And after having their skin analyzed, it was confirmed that Dave had ‘marginally better skin’.

If you would like to see part of the show, you can check it out here!

Interview with David Fisher about his calorie restriction diet in 2019

How long have you been practicing CR and what made you want to try out the diet in the first place?

I’ve been on CR for about 30 years, although I didn’t reduce my calories all in one go, I stepped them down over about 5 years.

I decided to try CR when I read that experiments with rats had shown that when CR’d, they lived longer than controls who ate a normal diet.

Can you tell us a little about your CR diet?

I am currently eating a vegan diet for five days of the week. For the other two days, I will eat non-vegan and include wild fish (usually). I also fast once a week.

I eat twice a day, once between 11 am and 1 pm, and once at either 5 pm or 6 pm.

Both meals usually consist of some nuts, a leafy salad, some form of pulse, mushrooms, vegetables, and occasionally some whole grain.

The earlier meal usually contains fruit. On the non-vegan day, the second meal would contain, for instance, wild salmon or scallops.

My calorie intake averages around 1700 kcal/day over the week.

Do you take any supplements? Which are your favorites?

I take one-sixth of a daily vitamin supplement, vitamin D, carnosine, and some plant extracts. I also take NAC because although my homocysteine level was normal, I wanted to reduce it to the bottom end of the normal range. I have just started taking nicotinamide riboside as well.

I have reservations about supplements as it’s difficult to be sure of their quality, but my feeling is some supplementation is worthwhile, especially as you get older.

How is your health holding up? Do you have frequent blood tests to measure things like glucose, blood pressure, and cholesterol?

My health seems to be holding up well. I went through the Health Nucleus testing at Human Longevity Inc last November (2018) and no worrying lesions were found.

They also reported that my visceral fat quantity was below the normal range, the balance test result was in the 98th percentile, and coronary calcium score was zero. I do have regular blood tests done.

You had your telomere length checked and compared against Michael Mosley. Since that time, have you had your telomeres measured again?

I haven’t had my telomere length measured for many years. I’m not sure how informative that test is, but I may get it done out of interest. If I do, I will let you know the result.

How do you deal with work and stress? Studies show that managing stress is a big factor in aging well.

A few years ago I rearranged my business and financial affairs to reduce risk and stress. I also practice meditation and try to have an attitude informed by the philosophy of Stoicism and Buddhism.

One of the problems caused by stress is raised blood sugar – so I wear a continuous blood glucose monitor which allows me to see when it is raised and when I need to exercise to bring it down quickly.

Many people were surprised by how young you looked in your TV interviews a few years ago. Do you think that is down to diet or genetics?





Genetics must play a role but my opinion is that diet is more important. We know for instance that CR or fasting can upregulate some cellular repair processes and it seems likely that this would affect appearance eventually. Also just carrying extra bodyweight often makes someone look older.

Do you take care of your skin and dye your hair?

If I do look younger, I would say that the most influential factors would be that I have not damaged the microcapillaries in my skin by smoking, and have used sunblock to lessen damage from ultraviolet light.

I’ve also maintained a good quality diet, held a constant weight, and have exercised enough to maintain good blood circulation.

However, I also dye my hair back to the original color and have had skin needling treatments, which seem to increase collagen production to younger levels. I think it helps.

You said that you’re on CR to live long enough to take advantage of future medical breakthroughs which can reverse aging. Are you aware of Senolytics, NR/NMN, Rapamycin, and Metformin?

Yes, I am aware of those things. I have recently started taking NR, but the effect of some of these is similar to the effects of CR, so people who have been on CR for some time should probably expect a smaller benefit.

I am excited about senolytics, as senescent cells do appear to be one of the root causes of aging, and the experimental results seem impressive. I have taken a round of fisetin as a senolytic, and will probably repeat that at intervals.

Read more about NMN, senolytics, and moving beyond CR.

Do you think that you partly influenced Michael Mosley to make changes to his diet after you both took part in health tests to compare biological age? And secondly, are there any plans for a follow-up with him for another round of tests?

He has looked into a number of forms of diet and exercise, but I’m not aware of influencing him. There are no plans for a follow-up, although I would be willing.

Would you like to promote anything that is important to you?

I would point everyone to the SENS Research Foundation, I believe the biggest breakthroughs in rejuvenation research will come from there.



Is there anything else you’d like to add that people might find interesting about your diet and lifestyle?

I would suggest people have their blood iron levels checked, most don’t think of it but high iron can be damaging and is apparently quite common, especially in men and postmenopausal women.

I donate blood to lower my serum transferrin saturation to the bottom of the normal range, although you do have to be careful not to overdo it.

I also think air quality is a neglected health issue. Where I live you might expect the air to be reasonably good quality, but a particle meter showed that in fact, it is very poor, mainly I think due to people using wood-burning stoves. I had to install air filtration equipment to improve it to an acceptable level in my home.

Other interviews which might interest you