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Health at every size: Where do we stand?

Robbie Puddick
Written by

Robbie Puddick

Medically reviewed by

Fiona Moncrieff

8 min read
Last updated May 2025
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Jump to: Understanding the HAES movement | The biological impact of body fat | Beyond BMI: Rethinking healthy weight | The role of lifestyle in health | Finding your ‘best weight’ | Take home message

The Health at Every Size (HAES) movement offers valuable principles for reducing weight stigma and promoting body acceptance.

However, the relationship between weight and health requires a more nuanced perspective, and one that doesn’t seem to be acknowledged by the HAES movement.

Research shows that excess body fat, particularly visceral fat stored around organs, can directly affect our health through mechanisms like insulin resistance and increased inflammation.

Insulin resistance and chronic inflammation contribute to the development of lifestyle diseases like type 2 diabetes and cardiovascular disease, independent of other lifestyle factors.

Still, BMI has significant limitations as a health measure. It fails to distinguish between fat and muscle, account for fat distribution, or consider differences based on age, gender, or ethnicity.

At Second Nature, we want to highlight the health impacts of excess body fat and the importance of reducing weight stigma and encouraging healthy body image, focusing on sustainable health behaviours rather than arbitrary weight targets.

Research demonstrates that people who maintain key lifestyle habits – regular physical activity, balanced nutrition, not smoking, and moderate alcohol consumption – have substantially reduced risks of chronic disease across all BMI categories.

The concept of finding your ‘best weight’ – the weight you can maintain while living a healthy, enjoyable lifestyle – offers a more realistic and compassionate approach than pursuing strict BMI targets.

This perspective acknowledges the impact that excess body fat can have on our health, while supporting individualised health journeys free from stigma.

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Understanding the HAES movement

The Health at Every Size movement emerged as a response to widespread weight stigma and the potential harms of weight-focused approaches to health.

Weight stigma encompasses negative attitudes, stereotypes, and discrimination that people experience because of their body weight, including social exclusion and unfair treatment in healthcare and employment.

This stigma causes measurable harm, leading to psychological distress, avoidance of health services, and poorer health outcomes beyond the direct effects of weight itself.

In the UK healthcare system, studies have found that weight stigma can lead to delayed or avoided medical care, with those living with obesity reporting they’ve postponed seeking healthcare due to concerns about weight-related judgement.

HAES promotes several key principles that offer a valuable counterbalance to a culture often equating thinness with health:

  • Respect for body diversity and acceptance of different body sizes
  • Reducing weight stigma in healthcare and society
  • Focusing on health-promoting behaviours rather than weight as the primary measure of health
  • Eating based on internal cues like hunger and satisfaction
  • Finding joy in movement rather than exercising primarily for weight loss

At Second Nature, we firmly support reducing weight stigma and promoting positive, sustainable health behaviours rather than restrictive dieting or quick fixes.

However, while embracing many aspects of the HAES philosophy, we take a more nuanced view on the relationship between weight and health based on the science of how excess body fat can impact our health.

The biological impact of excess body fat

Research shows that excess body fat, particularly when stored around our organs (visceral fat), can directly impact metabolic health through several specific pathways.

Fat cells aren’t passive storage units; they’re metabolically active tissues that communicate with the rest of our body.

Fat cells release compounds into the bloodstream that influence how our body functions.

When these cells enlarge due to excess energy storage, they release an excess amount of these compounds that adversely affect how well our body functions.

As fat cells enlarge, particularly in visceral areas surrounding organs, they become less efficient at responding to insulin, the hormone that helps regulate blood sugar.

This cellular resistance creates a cascade effect: our pancreas produces more insulin to compensate, leading to chronically elevated insulin levels that further disrupt metabolic processes throughout our body.

Visceral fat (surrounding internal organs) is typically more harmful than subcutaneous fat (the fat beneath our skin).

This explains why waist circumference often predicts health risks better than BMI alone. UK health guidelines now recognise this distinction, with NHS recommendations focusing on waist measurement as a complementary assessment to BMI.

However, subcutaneous fat can also become problematic when the size of these cells becomes too large.

We discuss this process in more detail in our series of articles on the personal fat threshold.

These biological mechanisms help explain why excess body fat can increase the risk of conditions like type 2 diabetes, heart disease, and certain cancers, independent of other lifestyle factors.

Taken together, it’s clear that excess body fat poses inherent health risks that can’t be entirely mitigated by other lifestyle factors alone.

Beyond BMI: Rethinking healthy weight

While recognising the health implications of excess body fat, we must acknowledge that standard measures like BMI have significant limitations that render them inadequate as standalone health indicators.

BMI was developed primarily from data on white European men in the 19th century, making it problematic when applied universally across different ethnicities, ages, and genders.

For example, research shows that people of Asian descent may experience metabolic health complications at lower BMI thresholds than European populations.

In contrast, those of African descent might maintain metabolic health at higher BMI levels.

The measure fundamentally fails to distinguish between different types of body mass.

Consider two people with identical BMI measurements of 27: one could be a rugby player with substantial muscle mass and minimal visceral fat, while another might have little muscle but significant visceral fat surrounding their organs.

Despite sharing the same BMI classification, their metabolic health profiles and associated health risks would differ dramatically.

BMI provides no information about fat distribution, a crucial factor in determining health risks.

Due to these limitations, BMI should be viewed as a simple screening tool rather than a definitive health measure.

Other factors, such as waist circumference, body composition, and metabolic health markers like blood pressure, blood glucose, and lipid profiles, often provide more meaningful information about an individual’s health status.

What constitutes a ‘healthy weight’ varies significantly between individuals based on factors like genetics, body composition, fat distribution, overall lifestyle habits, and individual health markers.

This means there’s much more flexibility in what defines a ‘healthy weight’ than is commonly understood.

Not everyone needs to achieve a ‘normal’ BMI to experience significant health benefits.

The role of lifestyle in health, regardless of weight

Adopting healthy lifestyle habits can substantially improve health outcomes across all weight categories.

A landmark study published in the Journal of the American Board of Family Medicine followed over 11,000 individuals and found that people who maintained four key lifestyle habits had significantly reduced mortality risk regardless of their BMI.

These four key habits were:

  • Regular physical activity (at least 150 minutes of moderate activity weekly)
  • A healthy diet based on whole foods
  • Not smoking
  • Moderate alcohol consumption (within UK guidelines of 14 units weekly)

Participants who maintained these habits showed a 50-60% reduction in all-cause mortality compared to those who didn’t, even when they had identical BMI measurements.

This research demonstrates that our behaviour and overall lifestyles significantly impact health, independent of weight status.

Lifestyle improvements typically yield substantial health benefits for individuals with higher BMI measurements, even without significant weight change.

Research shows that relatively modest improvements in fitness can reduce cardiovascular mortality risk by 50% or more, regardless of whether weight changes.

Similarly, dietary patterns rich in whole foods like vegetables, fruits, whole grains, meat, fish, seafood, nuts, and seeds improve health across all weight categories.

These findings don’t suggest that weight has no impact on health (as we’ve discussed above), but they highlight that:

  • Healthy behaviours improve health at any size
  • The relationship between weight and health is complex and individual
  • Many people can achieve excellent health without reaching a ‘normal’ BMI

At Second Nature, we encourage focusing on sustainable lifestyle changes that improve overall health rather than solely pursuing weight loss as the primary goal.

When we build healthy habits, weight often finds a natural balance supporting the lifestyle we want to lead, finding our ‘best weight.’

Finding your ‘best weight’

Rather than aiming for a specific BMI target, we encourage the concept of finding your ‘best weight’ – the weight you can maintain while living a healthy, enjoyable lifestyle that supports physical and mental wellbeing.

Your best weight might be:

  • The weight you naturally maintain when eating nutritious foods you enjoy, moving regularly, managing stress, and sleeping well
  • A weight that supports your energy levels and allows you to participate fully in activities you value
  • A weight that can be maintained without restrictive eating patterns or excessive exercise
  • A weight that supports positive markers of health, like healthy blood sugar and blood pressure

For some people, this best weight will fall within conventional BMI categories; for others, it won’t, and that’s absolutely fine.

The key is sustainability and overall health, not achieving an arbitrary number.

Finding your best weight involves:

1 – Listening to your body’s signals. This means paying attention to hunger and fullness cues, energy levels, sleep quality, and how different foods and activities make you feel.

Your body often communicates valuable information about what supports its optimal functioning.

2 – Focusing on sustainable habits rather than quick fixes. Small, consistent changes maintained over time yield far better results than dramatic but unsustainable approaches.

Adding a daily 15-minute walk that you enjoy and can maintain for years provides more health benefits than an intense exercise regimen abandoned after three weeks.

3 – Recognising that health encompasses physical, mental, and social wellbeing. A truly healthy weight supports all these dimensions.

If maintaining a particular weight requires practices that harm your mental health or social connections, it’s not your best weight.

4 – Regularly assessing health markers beyond the scale. Blood pressure, blood sugar, fitness levels, energy levels, and mood provide more comprehensive information about how your current weight and lifestyle support your health.

This approach acknowledges biological realities while supporting individualised health journeys free from stigma, shame, or oversimplification.

Take home message

At Second Nature, we believe in taking a balanced, evidence-based approach to weight and health that bridges the valuable insights from the HAES movement with current scientific understanding of metabolic health:

  • We recognise that excess body fat, particularly visceral fat, can negatively impact our health
  • We understand that BMI has significant limitations and that ‘healthy weight’ is highly individual
  • We emphasise that healthy lifestyle habits improve health outcomes regardless of weight
  • We support finding a sustainable ‘best weight’ rather than pursuing arbitrary BMI targets
  • We oppose weight stigma and promote body respect and compassionate self-care

This perspective allows us to acknowledge the health implications of excess body fat while supporting a compassionate, individualised approach to health that doesn’t define worth or health solely by body size.

It recognises both the important contributions of the HAES movement in combating weight stigma and the biological realities of how body fat affects metabolic health.

By focusing on sustainable lifestyle changes, developing a healthy relationship with food and movement, and defining health more holistically, individuals can improve wellbeing at any size.

This approach embraces body diversity while acknowledging the complex relationship between weight and health, offering a middle path that prioritises physical health and psychological wellbeing.

Second Nature’s approach

Second Nature provides evidence-based weight-loss programmes that incorporate this balanced perspective.

Our approach focuses on sustainable habit change, psychological wellbeing, and metabolic health rather than pursuing arbitrary weight targets.

By combining behavioural psychology with nutritional science, we help individuals develop lasting healthy habits that support finding their ‘best weight’ – whatever that may be for their unique body and circumstances.

For more information about our programmes and approach, visit our homepage.

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Start with Mounjaro, transition to habit-based health with our support

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