Which is better? "Eat Less" or "Move More"?

Much of my evolution as a practitioner has come from examining my own biases and seeing where there might be evidence to contradict them. Some of this evidence may come in the form of experience in working with large numbers of clients. It may come from randomized controlled trials. It may come from research reviews and meta analyses. While I take into consideration the hierarchy of evidence I also don’t discount the prolific evidence that we see in those around us who are working to improve the nutritional and health outcomes of others. That data, while not being as accurate or as detailed as that obtained in a metabolic ward or research laboratory, might actually hold far more utility. There is a lot to be said for real world applications. 

This real world application has led to the observation that those who walk more tend to have an easier time managing weight loss long term. While we have seen some research confirm that bias, there has also been a backlash that proposes we have a set point of caloric output that we just can’t outwork; lowering calories is the only option. But having worked with well over a thousand clients in my career, and the thousands more that my colleagues and peers have observed, seem to tell a different story.

Sometimes, we have a good week and there is research that confirms the hunches of my peers and myself that we have gleaned through working with this large cross section of people. Recently, a review in the journal Cell was one such instance. The journal review, titled “Obesity treatment: Weight loss versus increasing fitness and physical activity for reducing health risks” Gaesser & Angadi, was released recently and makes a strong case for the use of physical activity rather than intentional weight loss to improve health markers. So what exactly does this mean?

To start, we should probably examine the ongoing “fight” between the two sides of the nutrition world. On one hand we have those who work on the side of intentional weight loss. For years we have long been under the impression that the fastest way to improve health markers in obese populations is to lose weight. I know, hardly a huge logical jump there. In fact, we have mountains of evidence that states that even as little as 10% reduction in body weight can result in relatively significant changes in metabolic health. Who is gonna argue with that?

Well, on the other side we have the weight neutral or anti-diet camp that believes that any type of intentional weight loss is psychologically damaging and therefore goes against any kind of health directed outcome. They will cite a litany of recent research that shows better outcomes long term for those with obesity who use behavioral approaches to health rather than diet. Both camps have Rds, PhDs, MDs and tons of influencers helping to propagate their message. So which side is right? As is usually the case, the reality is probably somewhere in the messy middle.

Weight loss, in and of itself, is likely a double edged sword. It can be a psychological disaster if done for the wrong reasons or done in a way that is potentially damaging for certain populations. On the other hand, it can be a completely innocuous process that gives the person freedom of choice and change when done in a responsible manner as long as they have the skills and tools to manage it on the behavioral level. It’s all context.

Much of my career has been spent on intentional weight loss. In many ways it still is, however, I use much different strategies and tools than I once did. While most people will come to me with goals of fat loss, it is usually those who have struggled through years of traditional dieting with either minimal results or an inability to maintain those results after the fact. It is these populations, in particular, that the anti-diet crowd is referencing when they say that diets don’t work. And to their credit, they are right. Yet the idea that any attempt at weight loss is somehow a negative and that people are only trying to lose weight due to societal constraints and pressures is both myopic and coercive. It is not our role as practitioners to dictate how our clients or patients want to live but rather to help them to make the choices that will best serve their goals. Of course, if they are engaging in behaviors that are damaging or dangerous it is my role to both express my concern and refer out to a mental health professional. 

Now, on the other side we often have those who sell thinness as a proxy for happiness. This is absolutely unethical and anathema to everything we should stand for as health and fitness professionals. One’s body is not indicative of their mental well being. It is not a statement on morality. It is not indicative of desire. In fact, our body composition is more than likely a conglomeration of factors beyond our control. Those of us who have been successful in molding our bodies into something outside of the norm are the outliers. And yes, that includes almost everyone in fitness (I mean, we all just wanted jobs where we get paid to work out). 

Weight neutral approaches can lead to healthy weight loss in overweight and obese individuals even when the objective is not “intentional weight loss”. While there isn’t a lot of support for the idea of mindfulness based practices being efficacious for fat loss, the behavioral changes that can come along with a mindfulness practice will absolutely aid in the maintenance of any change that does occur. Being more aware can help reduce shame around food and reduce the frequency of binge episodes in those with a propensity towards disordered eating. Acceptance based therapies can help those with negative body image issues start to accept where they are and improve relationships with food. So while none of these practices are meant to reduce body weight, they can have a profound effect on the daily behaviors of these individuals which can allow them space to decide, on their own, if weight loss is a worthwhile and emotionally safe pursuit.

What often gets lost here is the aspect of health related outcomes versus just that of weight management. When the two camps argue it is often used as a proxy. The anti-diet crowd will state that health can exist at any size (while simultaneously shaming those who choose intentional weight loss) as the intentional weight loss community will often belittle the health at any size movement in a stance of what I see as undercover fat shaming in the name of public health. What we do know is that using shame as a motivator is almost never useful at producing desired public health outcomes… which anyone who has an anti-vaxxer in their family can surely attest to. It has been an abject failure when it comes to the obesity epidemic.

So while we know that “eat less, move more” is pretty terrible advice for fat loss, what about just pushing the move more narrative for health outcomes? That is exactly what this recent paper examined. In the review the authors examine data from the last 40 years which shows an ever increasing number of people who actively diet yet we also have seen an increase in obesity of 300%. So clearly the focus on diet alone has not been one of success, even as more and more individuals express a desire to weigh less. The following chart shows the cycle of attempted weight loss and subsequent gain.

https://doi.org/10.1016/j.isci.2021.102995

Instead of focusing on the idea of BMI as a predictor of health outcomes (the long accepted view being that higher BMI increases mortality risk), the authors chose instead to look to see if cardiorespiratory fitness (CRF) and physical activity (PA) could show similar or better results. The reasoning behind this shift in focus being that a review of the literature has shown that BMI in and of itself is not linearly related to increased risk of mortality. In fact, older adults with the lowest mortality risk fell in the overweight category. They do point out that mortality risk is multifactorial and to assign just BMI is a bit misleading but the point is that there are inconsistencies that need to be addressed. They also brought up a recent analysis that found fat mass and fat free mass tend to show opposite correlations to mortality, so you should definitely be lifting.

In the realm of cardiorespiratory fitness they showed some pretty promising correlations. According to the meta-analysis cited that includes both BMI and CRF, there appears to be a significant reduction in the mortality risk associated by a high BMI by showing a high level of CRF. It also shows a higher risk of all cause mortality in those with a low CRF regardless of their BMI. While there are variables the authors acknowledge could hedge the bets toward the CRF cohort (mainly that of higher BMIs being the cause of higher fat free mass) they still maintain that those variables alone are unlikely to be responsible for the considerable variance in outcome. There is also reference to a number of studies in the realm of muscular fitness that show vast improvements in all-cause mortality which many of my colleagues have written about extensively so I won’t jabber on about it here. However, if you would like to read more about those studies I would highly recommend subscribing to Deconstruct Nutrition.

https://doi.org/10.1016/j.isci.2021.102995

The bigger difference between this analysis and those of the past is that, according to the authors, no meta-analyses have investigated the effect of PA on this same relationship. One of these issues seems to be the subjective nature of what constitutes PA and therefore making it difficult to standardize differences. That notwithstanding, in the authors’ review of studies they found that once PA was adjusted for BMI was unrelated to mortality risk. They go on to look at epidemiological studies that show active adults with obesity have a similar risk to non-obese inactive adults, specifically citing the NHANES study. That’s a pretty solid argument for getting your activity in. 

After presenting their case that there’s a lack of evidence tying BMI to all-cause mortality as well as the advantages of CRF and PA, the authors pivot a bit to dieting and diet culture. They attempt to find correlations between intentional weight loss and mortality through a variety of observational studies and randomized controlled trials. Let’s just say the results were less than conclusive. While there wasn’t an increase in mortality risk with intentional weight loss, there also didn’t appear to be a significant decrease. Now, this doesn’t mean that actual weight loss doesn’t have an impact on all cause mortality, it just shows that attempts at weight loss won’t reduce your risk of death, which is less surprising when we acknowledge that long term weight management is often unsuccessful.

The authors then proceed to look at medical interventions for weight loss and the effects on all-cause mortality. They begin with liposuction which they acknowledge is probably a poor example to underscore their hypothesis in that it is removing subcutaneous fat. The larger risk for all-cause mortality is that of adipose tissue or the fat that grows around our vital organs. So to use that as an example is probably not going to yield a huge difference in life span. So what about bariatric surgery?

I have been fascinated by the effects of bariatric surgery when I learned that it can reverse type 2 diabetes within days of the surgical procedure. This underscores the authors’ claim that bodyfat in and of itself is not the primary driver of t2d but one of many factors. However, the complexities of type 2 diabetes and metabolic dysregulation can’t likely be pinned on one cause. So again, this example falls a bit flat.

The last main point that the authors come to in this study is that the focus on weight loss has a distinct negative, which they refer to as weight cycling. This is simply the act of losing and regaining weight repeatedly over a lifetime. In the meta-analyses included in their review, there was a significant increase in risk of all cause mortality across all BMI ranges among those who had a history of weight cycling. The larger the swings in weight, the larger the risk. The authors go on to argue that the increased risk of high BMI may be due to a history of weight cycling and in particular sarcopenic obesity. This is something I have spoken of frequently and what Dr Ben House refers to as the Wall-E Effect. Essentially, people crash diet with no regard to protein consumption or resistance training and lose significant amounts of muscle mass. When they regain the weight it is a majority of fat gain and end up at a higher body fat percentage while at the same weight prior. Rinse and repeat several times and we are, in essence, just a skeleton holding onto mostly fat mass. That is a tough place for the body to be. 

The authors then go on to look at individual health markers such as blood pressure, blood glucose and lipid values and find similar outcomes. This isn’t super surprising to me as Dr Ben House and Dr Tommy Wood had presented on this last year. Still, to see a published review of the literature that supports the idea of increasing fitness to combat metabolic disease is refreshing. 

Overall, the prognosis of diet culture seems grim. Especially when presented with things as frightening as sarcopenic obesity. However, I choose to see the positive in studies like this. As a professional in the fitness and nutrition sphere I believe that it’s important that we not be myopic in our approaches and allow ourselves the opportunity to help others based on their needs and not our own biases. 

The conclusion does not need to be dichotomous; we can use intentional weight loss and weight neutral approaches interchangeably and as tools rather than dogmatic belief structures. There will be clients who can safely use intentional weight loss strategies to both lose and maintain weight loss long term as well as those who may encounter psychological distress or find those strategies unsustainable. It is up to us as professionals to help guide people along the path that is best for them. That does not mean we dictate or diminish their goals; it’s quite the opposite. We can look to our toolbox and choose the right tools to help them best realize and maintain their desired outcome. To know that we can also help clients improve their health outcomes through both intentional weight loss and weight neutral approaches is just icing on the cake. Now you have a pretty comprehensive review of the literature to confidently say, both movement and weight loss might help you live longer. And that’s pretty cool.

A full open source text of the review Obesity treatment: Weight loss versus increasing fitness and physical activity for reducing health risks Gaesser & Angadi 2021 https://doi.org/10.1016/j.isci.2021.102995

available at https://www.sciencedirect.com/science/article/pii/S2589004221009639