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Monday, February 18, 2019

Review: The Longevity Diet

Having recently read a crack-pot diet book, I was wary when I saw The Longevity Diet. To my relief, this is not a crackpot diet book. Valter Longo instead of peppering his text with anecdote after anecdote, refers to clinical trials, and is careful to couch his conclusions with caveats:
Quinn, who had recently been diagnosed with breast cancer and was about to undergo chemotherapy. Shortly after the story appeared, one of the judge’s friends called me at USC and informed me that Quinn had been fasting for eight days. I was horrified. “That’s crazy,” I said. “Please tell your friend to start eating immediately.” (Loc 1667)
 Similarly, he discusses his theory that too much protein is actually bad for you, especially if it triggers growth hormone:
Although obesity is known to increase one’s risk of diabetes, protein intake may be just as big of a factor. One study following forty thousand men for up to twenty years showed a twofold increased risk for diabetes associated with a low-carbohydrate, high-protein diet.7 Those results are consistent with our 2014 study of six thousand people in the United States indicating increased diabetes risk in those with the highest protein intake, although the small population size limited the significance of our results. (Kindle Loc 1957)
Note that he refers to a 6000 person study as a small population size and discusses the difficulty of generalizing from a small sample size to the entire population.

OK, let's look at Dr. Longo's arguments:

  1. It's well known that the Mediterranean diet is good for you, but certain other places in the world (e.g., Okinawa Japan, and Loma Linda, California) also have a history of producing long lived humans
  2. The commonality between the diets of all these places is a high emphasis on plant based diet, low use of processed food, low dependence on animal based protein (and not too much protein at that), and the use of fish as the main source of protein.
  3. Fasting has been a human tradition in the past, including intermittent fasting. Clinical trials indicate that a fast-mimicking diet (FMD) has positive results for cancer patients undergoing chemotherapy: reduction in nausea, as well as more effective elimination of cancer cells, and faster recovery.
  4. Diet should vary depending on needs throughout the life cycle. In adult and middle age, a lower calorie diet with less protein is associated with better longevity, while in old age (past 65), increasing protein intake becomes more necessary to preserve muscle and increase weight for better survivability of age-related illness
His recommendations for healthy people is to adopt a traditional diet. The most cranky type of this advice is to eat what your ancestors ate, the reasoning being that your ancestors would have figured out what foods had poor fit for your genotype. This struck me as the most iffy part of the book, indicating that a German person who moved to say, India, shouldn't eat curry, even if that diet was adapted for the region for certain specific reasons.

The diet recommendations are fairly strict: 0.31 to 0.36 grams of protein per pound of body weight per day. That's about 40-47g of protein per day for a 130 pound person (an 8oz steak, for instance, has 56g of protein, blowing that budget out of the water). The rest of your calorie intake pretty much has to come from complex carbohydrates and "good oils" like olive oil!

One limitation of the book is that the doctor thinks that exercise is an hour of fast walking a day (or fastish cycling), and doesn't factor in diets for people who might be more active (or say, engaged in strength training). The book continually warns that if you're over 65, the fasting protocol is not for you, and that you should try to do it only as part of a clinical trial, etc. and then proceeds to tell you how it works! He does point you at a commercial program called ProLon, but disclaims that he's making any money from it.

The fasting protocol looks doable (1 transition day, 5 days of very little food, and then 1 transition day), so it's the long term diet that would be difficult to maintain, though the book does have a recipe in the back that has recommendations (basically, no animal protein means milks, yogurts, etc have to have plant-based substitutes), with only an occasional egg.

In any case, I can't dismiss this book as a crack pot diet book, but the program seems challenging and worth investigating if you're trying to lose weight (I'm not), or have some other health issues. The caveat says to not try this if you're already diabetic without medical supervision though!

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