Recently, I was interviewed by Steven Bartlett on the Diary Of A CEO podcast about my work on obesity. While I have done a gazillion previous podcasts, either as host or guest, this one stood out for three reasons: first, the interview was long-form, lasting for 1 hour and 52 mins, and was released in its entirety, with minimal editing; second, in addition to the normal audio recording, it was filmed with multiple cameras, and posted online in full technicolour; and third, the scale of the audience. I’m not sure how many listeners tuned in to the actual podcast, but at time of writing, 2.5 million(!!) people had viewed the ‘feature-length’ interview on YouTube.
What soon became clear was, of the millions that watched, many felt the need to comment loudly on social media (while tagging and @-ing me) on my appearance, vis-à-vis my expertise in obesity. I am, shall we say, not at my ‘fighting weight’, having gained more than four kilos (10 pounds) during the past few COVID years. This, coupled with my sartorial error of appearing at the interview in a roll-neck sweater (although in my defence I was not expecting to be filmed), resulted in a multitude of comments like, “Why would you trust a man with moobs about weight and nutrition?” Ouch.
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This did get me thinking, though. If I, a slightly squashy middle-aged professor, was on the receiving end of such comments, what horrors must someone with obesity be facing on a daily basis? It is interesting that if I were to negatively comment on someone’s gender, sexual orientation or ethnicity in public, I would rightly lose my job. Yet today, many feel it entirely appropriate to comment on someone’s size or shape. Weight stigma, sadly, continues to be rife. It is not only cruel, but counterproductive, and yet inexplicably ubiquitous in society. It has led to the emergence of the body-positivity movement.
‘Body positivity’ was founded on the belief that all of us should have a positive body image, and advocates the acceptance of all bodies, regardless of physical ability, size, gender, race or appearance, and I completely understand its emergence as a protest to ‘fat-shaming’. I fear, however, that some within the movement have gone too far with regards to the ‘health at every size’ messaging, and are ignoring the science. What is unequivocal, and please don’t shoot the messenger, is that carrying too much fat is bad for your health. This leads to two questions: why is carrying too much fat bad for you, and how much is too much fat?
First, why is carrying too much fat bad? In large part, people misunderstand what happens when they gain or lose weight; they think that they are gaining fat cells or losing fat cells. This is not true. You have to consider your fat cells like balloons; they get bigger when you gain weight, and they get smaller when you lose weight. The actual number of fat cells doesn’t change by much at all. The safest place to store fat is in fat cells.
Like all balloons, fat cells will expand until they can’t expand any more, but unlike balloons, they don’t pop (thank goodness). This is when the trouble begins, because once our fat cells are full, then the fat has to go somewhere else, and ends up in our muscles or our liver, for example. While muscles and the liver are designed to store some fat, too much of it begins to adversely affect their function, in a phenomenon known as ‘lipotoxicity’, literally meaning fat poisoning. Thus, when we are carrying more fat than we can safely store, that is when we tilt into diseases such as type 2 diabetes, heart disease and certain cancers.
Second, how much is too much fat? So here is the interesting thing: depending on our individual biology, our fat cells are able to expand to different sizes before becoming full. So East Asians (such as Chinese folk like me) and South Asians (such as Indians, Pakistanis and Bangladeshis) don’t have to put on that much weight before increasing their risk of getting type 2 diabetes, for example. Whereas others, including white people and, famously, Polynesians, can gain a lot more weight before becoming ill, in large part, due to the expandability of their fat cells.
The degree to which our fat cells can expand has powerful genetic influences and informs our differing safe fat-carrying capacities. So in any given population there is most definitely health present at many sizes; with some larger folk being the picture of metabolic health, and other lean and fit-looking people with type 2 diabetes.
But here is the critical take-home message: for any given individual, there cannot be health at every size, because if you surpass your own safe fat-carrying capacity, you WILL become ill. I am not saying this to be body negative, and I am certainly not judging or blaming anyone who chooses not to lose weight, or who has tried and been unsuccessful. I am simply stating a crystal-clear biological fact.
In a mature society, we should be able to hold two thoughts in our head simultaneously; that living with obesity is not healthy, and those with obesity are not to blame. The ability to determine a person’s safe fat-carrying capacity is the subject of cutting-edge genetic and biological research, and would be a game-changer, transforming the way we consider the definition of ‘obesity’ and who actually needs to lose weight.