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Did Yo-Yo Dieting Cause Tom Hanks' Diabetes?

MedpageToday

Just "like a box of chocolates. You never know what you're gonna get" when you have Tom Hanks as a guest on your show.

So David Letterman found out when he was talking to Hanks about his upcoming movie, Captain Phillips. When complementing Hanks on his svelter figure, Hanks said:

I went to the doctor, and he said, 'You know those high blood sugar numbers you've been dealing with since you were 36? Well, you've graduated! You've got Type 2 diabetes, young man.'
Hanks went on to say that it is a "controllable" condition and that he is working to "maintain the temple."

Tom Hanks is one of those actors who is well known for the dramatic, voluntary weight gains and losses he has undergone for a number of his film roles:
  • Hanks gained 30 pounds to play baseball coach Jimmy Dugan in 1992's "A League of Their Own." 
  • He lost 55 pounds playing a FedEx employee on an abandoned island after a plane crash in "."
  • He won his first Academy Award for Best Actor in the 1993 film  for which he lost 26 pounds to play a lawyer with AIDS.

A number of media outlets are questioning whether Hanks' diabetes was caused by this degree of weight fluctuation. But Hanks doesn't think that's the main reason. Speaking at a for Captain Phillips on Wednesday, he said:

"Gaining and losing of weight may have had something to do with this because you eat so much bad food and you don't get any exercise when you're heavy."
"But I think I was genetically inclined to get it and I think it actually and goes back to a lifestyle I've been leading ever since I was 7 years old, as opposed to 36."

Weight cycling, also known as yo-yo dieting, is a term  coined by Kelly D. Brownell at Yale University to describe a process whereby the dieter is initially successful in the pursuit of weight loss but is unsuccessful in maintaining the loss long-term and begins to gain the weight back. The dieter then seeks to lose the regained weight, and the cycle begins again.

What is the evidence regarding weight fluctuation and Type 2 diabetes?

As is often the case in topics such as this, the evidence is mixed.

A study by et.al in the American Journal of Epidemiology looked at the association between weight patterns during middle age and the incidence of type 2 diabetes using a subset (n = 1,476) of the Framingham Heart Study original cohort. They conclude that although being overweight or obese was associated with higher rates of diabetes, weight cycling was not associated with a higher incidence of diabetes.  In other words, weight itself was a more important factor than changes in weight.

Furthermore, concluded, based on epidemiological evidence, that weight cycling does not lead to an increased risk of mortality.

It has been shown that accumulation of proinflammatory immune cells in adipose tissue contributes to the development of obesity-associated disorders. , Alyssa Hasty, and their colleagues at Vanderbilt University alternated mice between high- and low-fat diets. They were trying to determine whether weight cycling altered the numbers of immune cells, inflammation, and insulin resistance in adipose tissue. They found that adipose tissue in mice who had been weight cycled do show an amplified T-cell response compared with mice that lost weight without cycling. Weight cycling also impaired systemic glucose tolerance and AT insulin sensitivity.

But there is some good news: , et.al. at the Fred Hutchinson Cancer Research Center, found that "a history of weight cycling does not impede successful participation in lifestyle interventions or alter the benefits of diet and/or exercise on body composition and metabolic outcomes."