FUNCTIONAL HEALTH GUIDE -- HELPING YOUR PET LOSE WEIGHT
Functional Health — Weight Loss & Body Composition
Functional Pet Weight Management 101
A Longevity-Focused Guide for Dogs and Cats
By Dr. Kevin Toman, The Longevity Vet
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Why Weight Is a Functional Health Issue
Weight is not cosmetic.
It is one of the most powerful, proven longevity levers in veterinary medicine.
If there were a single intervention shown to:
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extend lifespan
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delay disease
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reduce pain
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improve metabolic health
—independent of genetics—it would not be a supplement or a drug.
It would be maintaining a lean body condition.
This worksheet is a decision-support tool, not a diagnosis.
It is organized around The 3 Core Goals.
The 3 Core Goals
This worksheet is designed to help you:
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Clarify what matters most right now
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Determine the next best test (if any)
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Choose the most appropriate next step
Core Goal 1: Clarify What Matters Most Right Now
Why Weight Is a Late Marker
Visible weight gain is often the last sign of metabolic dysfunction.
Earlier changes commonly include:
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insulin resistance
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altered energy utilization
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chronic inflammation
By the time weight changes are obvious, biological stress has often been present for years.
Early Metabolic Red Flags
Patterns that deserve attention include:
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difficulty losing weight despite effort
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increased hunger or food-seeking behavior
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low or inconsistent energy
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abdominal fat gain
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abnormal triglycerides or lipid trends
The key question is not:
“Is my pet overweight?”
It is:
“Is my pet’s metabolism functioning efficiently?”
Core Goal 2: Determine the Next Best Test (If Any)
Not every pet struggling with weight requires immediate laboratory testing.
Functional Health helps clarify:
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when diet and lifestyle changes are appropriate first
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when body composition assessment adds value
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when metabolic testing helps explain resistance to weight loss
What to Evaluate First
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body condition and muscle mass (not just scale weight)
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feeding patterns and calorie sources
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carbohydrate load and diet composition
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activity type and consistency
Testing is used intentionally, not reflexively.
Core Goal 3: Choose the Most Appropriate Next Step
Weight loss is not about extremes. It is about consistent, sustainable energy balance.
The Non-Negotiable Foundation: Energy Balance
All weight loss follows one rule:
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calories in > calories out → weight gain
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calories in < calories out → weight loss
Most pets are unintentionally overfed through:
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free-choice feeding
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treats and table scraps
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underestimated portion sizes
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calorie-dense foods
Why Moderate Calorie Control Works (The Evidence)
The Purina Life Span Study
The most important longevity study ever performed in dogs was a 14-year, controlled, lifetime feeding study.
Study highlights:
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48 Labrador Retrievers, paired as littermates
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One dog per pair fed to ideal body condition
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~25% fewer calories than full-fed littermates
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Feeding began at 8 weeks of age and continued for life
This was not starvation.
It was intentional, moderate calorie control.
Key Findings
Increased lifespan
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Lean-fed dogs lived 1.8 years longer
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Equivalent to ~15% lifespan extension
Delayed disease onset
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Age-related disease occurred ~3 years later
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Especially osteoarthritis, pain, and mobility decline
Improved metabolic health
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better insulin sensitivity
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healthier body composition
These dogs lived longer and better.
Practical Weight-Loss Interventions
First-Line Functional Health Strategies
Dietary composition
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reduced calorie density
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appropriate protein intake
Meal timing
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structured feeding
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elimination of free-choice grazing
Movement quality
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preserving muscle mass
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supporting joint health
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improving insulin sensitivity
Reducing Calories Without Increasing Hunger
Water addition
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increases food volume
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improves satiety
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especially valuable for cats on dry food
Fiber & psyllium
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slows gastric emptying
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reduces hunger behaviors
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improves compliance
Advanced Interventions (When Appropriate)
In some pets, diet alone is insufficient.
Advanced options may include:
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insulin-sensitizing strategies
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prescription longevity or metabolic medications
These tools must be:
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carefully supervised
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integrated into a broader plan
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adjusted over time
They are not shortcuts.
Dogs vs. Cats: Critical Differences
Dogs
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highly influenced by owner behavior
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respond well to structured feeding
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exercise tolerance varies by breed and age
Cats
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routine-oriented and metabolically sensitive
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must lose weight slowly
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at risk for hepatic lipidosis if weight loss is too rapid
Safe feline weight loss is typically 1–2% of body weight per week.
When to Escalate Beyond the Worksheet
A PET LONGEVITY CONSULT is appropriate when:
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weight loss stalls despite appropriate effort
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labs show metabolic stress
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multiple systems are affected (joints, inflammation, cognition)
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prescription metabolic or longevity medications are being considered
Expert guidance prevents frustration and trial-and-error.
Text link CTA:
Start a Pet Longevity Consult
The Longevity Takeaway
The Purina Life Span Study proved something extraordinary:
Maintaining a lean body condition is one of the most powerful longevity interventions available for dogs—and likely cats.
Not a supplement.
Not a trend.
Not a drug.
Just intentional, lifelong calorie moderation.
Weight management is not about aesthetics.
It is about:
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adding years
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reducing pain
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delaying disease
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preserving joy and mobility
And it is never too late to start.
Your Next Step
If weight or metabolic concerns are present:
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review related Functional Health Worksheets (metabolic health, arthritis, senior screening)
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focus on sustainable, biology-driven changes
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seek expert guidance if progress stalls
There is no single correct solution — only the appropriate next step for your pet today.
About These Worksheets
This worksheet is part of the Functional Health system developed at PetFunctionHealth.com, designed to identify early decline and guide long-term longevity strategy.