The link between weight and health: does weight loss really contribute to overall health?

Nutritionist

Weight loss does not mean being healthy

In our first article about the link between weight and health, we discussed of the concept of “healthy weight” and what science said about the body mass index (BMI). To continue, we address the limitations of scientific studies on the loss of weight and the concrete impacts of the weight-centered approach. For this article, several scientific literature reviews were consulted; you will find them at END.
In science, to establish the facts, it is necessary to rely on scientific studies (which test a hypothesis using experiments and/or observations on the ground). If you search the databases for studies concluding that a loss of weight improves health, you will find some, but several of them have limitations in their design and methodology.

The studies and their limits

Scientific studies testing the hypothesis that weight loss improves health have quite varied methodologies. Some offer an intervention (ex: dieting) while others observe without intervening, some have some dozens of participants while others have several tens of thousands (4) and some offer one plan while others offer another. Indicators of health measured also differ from one study to another: blood cholesterol, blood sugar, blood pressure, etc. However, all these variants influence the conclusions that can be drawn and can make it difficult to compare studies between them.

In addition to variability, the design and analysis of studies have certain limitations
non negligable:

  • Duration: several studies last less than a year: is the weight loss
    maintained after a year? What about health improvements? As a professional
    health, it is appropriate to propose an intervention that improves health on the
    long term.
  • Dropouts: many participants drop out prematurely without being
    always taken into account: why do they leave? In longer term studies
    (4 years or more) of a review of the literature consulted (2), the percentage of
    participants attending the follow-up appointment is on average only
    33%…
  • Maintenance: weight loss, sometimes quite limited (a few kg), is often not
    not maintained during the study, even if it is of short duration. In those of
    more than a year, in general, the more time passes, the more the kg recovers.

If we seek to prove that it is weight loss itself that improves health,
care must be taken to take into account the other variables that can influence this
last. Unfortunately, several studies ignore it in the analysis of their
results. Here are some of the variables in question:

  • Lifestyles: the composition of the diet and the physical activity offered
    in the study may have an impact on the health of participants regardless of the
    weight. For example, if participants have to eat more fruits and vegetables,
    only this change can decrease their risk of suffering from diseases
    chronicles…

  • Discrimination, including fatphobia: the heavier people are, the more they
    suffer from grossophobia, which negatively influences health
    regardless of the intervention.
  • Socio-economic status and social support influence stress levels
    and health. Having better social support helps to have better health.
In short, the link between weight and health being very complex, research does not allow us to so far to prove beyond any doubt that weight loss alone improves health and will improve it in the long run.

The weight-based approach

The majority of studies take into account the physical impact of recommending the loss of weight, but do not question certain concrete impacts in the daily lives of folks. Many healthcare professionals take a weight-based approach, that is to say, aiming for their patients to be at their “healthy weight”, with very good intentions, but this intervention can have several negative impacts.
This is particularly true when the intervention leads the person to seek a excessive weight loss. Every body has a weight range at which it is naturally created to be (called natural weight). The latter may be outside the BMI category of “healthy weight” and is determined by a long list of factors, including genetics, drugs used, socio-economic environment, diet, physical activity, restriction history and many more.
When the body loses weight beyond its natural weight range, it does everything in its power to bring it back (like a thermostat): increased hunger, cravings richer foods, compulsions (overeating), insomnia, decreased energy expenditure, etc. Also, the restriction necessary to achieve this leads to significant psychological impacts: obsession with food, dysmorphia body, depression, social isolation and reduced self-esteem.
Is it a beneficial intervention if not only its impact on health is not proven beyond any doubt but it also harms mental health? Prescribe a loss weight is easily done, but putting it into practice is no small feat (pardon the pun), nor without damage. At LauGau Nutrition, we consider the mental health of our patients while by helping them adopt lifestyle habits conducive to their physical health without restriction nor rigidity.

References:

1. Hunger, J.M., Smith, J.P. and Tomiyama, A.J. (2020), An Evidence-Based
Rationale for Adopting Weight- Inclusive Health Policy. Social Issues and Policy
Review, 14: 73-107. doi:10.1111/sipr.12062

2. 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;62(3): 220-233. doi:10.1037/0003-066X.62.3.220

3. Mauldin K, May M, Clifford D. The consequences of a weight‐centric approach to
healthcare: a case for a paradigm shift in how clinicians address body weight.
Nutr Clin Pract. 2022;1‐16. doi:10.1002/ncp.10885

4. Tomiyama AJ, Ahlstrom B, Mann T. Long‐term effects of dieting: is weight loss
related to health? Soc Personal Psychol Compass. 2013;7(12):861‐877.
doi:10.1111/spc3.12076

Maude Martinez, Nutritionist, Dt.P
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