It turns out diet and exercise aren't that important!

On the 22nd January 2024, and article I would describe as fairly monumental was published in Jama Open Network, entitled “Improvement of Social Isolation and Loneliness and Excess Mortality Risk in People With Ob-sity” (1). We need to talk about it.

Let me start by saying that we know there is a higher risk of mortality in higher weight individuals compared to their leaner counterparts, whether it is heart related, cancer, or indeed from all causes. But we don’t know why. Theories abound, but none of them are supported by the evidence.

Some argue that it doesn’t matter. Increased risk is increased risk, so all that matters is that we do something about it. The problem is, if you don’t know what is causing the risk, how are you supposed to improve it? Put another way, you can’t really fix a problem without getting to the underlying cause of it.

For the last few decades, experts have claimed that the way to reduce the raised morality risk in higher weight individuals is to get rid of the weight. Seems logical, right? But there’s really no evidence out there that supports this. The Look AHEAD study, for example, measured mortality rates in higher weight type 2 diabetics for over a decade (2). They believed that those who intentionally lost weight would have lower mortality rates. They were wrong. In fact, they ended the study early because of it.

Aside from the fact that weight loss is unsustainable, it doesn’t appear to be addressing the increased mortality rate (3). If anything, it’s making it worse. Which is why I welcome this study by Zhou et al. Because finally someone is taking a different approach.

They measured a slew of factors, including social isolation and loneliness scores, in 93 thousand + higher weight individuals and compared them to 305 thousand + controls. They followed them up between March 2006 and November 2021, and measured the mortality rate from cardiovascular disease, cancer, and all causes.

Here’s what they found.

Social isolation and loneliness increase mortality rates in people of all sizes. No surprises there. They also found that as the index of social isolation and loneliness went from highest to lowest, the mortality rates dropped significantly (from 36% to 9%) in the group of higher weight individuals compared to the controls.

Or, to put it another way, once we adjust for social isolation and loneliness, the association between being higher weight and excess mortality is significantly reduced. Which suggests that there is something other than visceral fat that causes poorer outcomes in Fat people. You don’t say?!

"Aside from the fact that weight loss is unsustainable, it doesn’t appear to be addressing the increased mortality rate."

Here’s what I found really interesting about this study. It’s not that Fat people with lower levels of social isolation appear to have a decreased risk of all-cause mortality. Its that social isolation was ranked higher than depression, anxiety, and lifestyle-related risk factors (such as alcohol, physical activity, and healthy diet) for estimating the risks of all-cause mortality, cancer-related mortality, AND CVD-related mortality.

You know what? I think in this case, pictures will speak a thousand words. Here’s a graph that shows the relative importance of risk factors for all-cause mortality in in the 93 thousand + higher weight participants.

Image: JAMA Netw Open. 2024;7(1):e2352824. doi:10.1001/jamanetworkopen.2023.52824

You’ll notice that smoking is top of the list.  The Townsend Deprivation Index is a measure of material deprivation in the UK (where this study was carried out), so it’s not surprising that it is number 3 on the list. Medical conditions such as diabetes and high blood pressure are known risk factors for mortality, which is why we spend so much time diagnosing and treating them. 

Social isolation is number 4 on this list. Healthy diet is number 12, below depression, low education, alcohol and eating disorders. Which is important to note because intentional weight loss is linked to three out of four of these. Now let’s look at the graph for Cardiovascular Mortality.

Image: JAMA Netw Open. 2024;7(1):e2352824. doi:10.1001/jamanetworkopen.2023.52824

Once again, smoking is by far the biggest risk factor. High blood pressure and diabetes have swapped places which may come as a surprise to some of you but doesn’t come as a surprise to me. Social isolation ranks higher than deprivation for cardiovascular mortality (and by that, I mean heart attacks, strokes etc). In this case, “healthy diet” is number 15 on the list. Finally, let’s look at cancer.

If there’s one thing I know about cancer is that it doesn’t discriminate. That’s why deprivation plays less of a role, although low education factors heavily here. As you can see, there are very few risk factors other than smoking that play a significant role in the mortality rates from cancer.

Image: JAMA Netw Open. 2024;7(1):e2352824. doi:10.1001/jamanetworkopen.2023.52824

"Social isolation, which is a recognised consequence of weight stigma, is far more important when it comes to mortality than diet and exercise."

Now this study was well designed and has many strengths. The sheer numbers and length of follow up for starters. But it’s not without its limitations. Most of the things measured here are self-reported. Questionnaires don’t leave much room for the nuance and complexity.

Social isolation was measured using the following three questions:

  • Including yourself, how many people are living together in your household?
  • How often do you visit friends or family or have them visit you?
  • Which of the following (sports club or gym, pub or social club, religious group, adult education class, other group activity) do you attend once a week or more often?

Loneliness was measured using two questions:

  • Do you often feel lonely?
  • How often are you able to confide in someone close to you?

So no, this study is by no means perfect. They never are. But it gives us some insight into what happens when a group of researchers decide to focus on something other than diet and exercise when it comes to the health of higher weight individuals. Imagine if they started researching weight cycling, or weight stigma, or discrimination?

The real take home point here is that social isolation, which is a recognised consequence of weight stigma, is far more important when it comes to mortality than diet and exercise. Put that in your pipe and smoke it fatphobes!


  1. Zhou J, Tang R, Wang X, Li X, Heianza Y, Qi L. Improvement of Social Isolation and Loneliness and Excess Mortality Risk in People With Obesity. JAMA Netw Open. 2024;7(1):e2352824.

  2. Look AHEAD Research Group, Wing RR, Bolin P, et al. Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes [published correction appears in N Engl J Med. 2014 May 8;370(19):1866]. N Engl J Med. 2013;369(2):145-154

  3. Mann T, Tomiyama AJ, Westling E, Lew AM, Samuels B, Chatman J. Medicare’s search for effective obesity treatments: diets are not the answer. Am Psychol. 2007 Apr;62(3):220-33.

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