Remember the 90s? Fat-free everything. SnackWell’s cookies. We were told fat would kill us.
Then suddenly: butter in your coffee. Bacon-wrapped everything. Fat became the hero and carbs became the villain.
And you’re sitting here thinking: Which one is actually right for MY body?
Here’s the truth nobody wants to tell you: Neither extreme is right. And what works for your keto-loving friend might be completely wrong for you.
Let me show you how to finally figure out what it is that YOUR body needs.
When We Got It Wrong: The Low-Fat Era
The 80s and 90s declared war on fat. The logic seemed simple: eating fat makes you fat, right?
So we ate fat-free cookies, fat-free salad dressing, fat-free everything. Food companies just replaced the fat with sugar and chemicals.
What actually happened?
- We got fatter
- Diabetes exploded
- Heart disease didn’t improve
- Everyone was hungry all the time
Oops.
Turns out, when you remove fat from food, you remove what makes you feel satisfied. You’re hungry an hour later. Plus, what most people don’t know is that your body actually NEEDS fat: for hormones, for brain function, and to absorb vitamins.
The Overcorrection: The High-Fat Revolution
Fast forward to the 2010s: Keto. Paleo. Carnivore. Suddenly fat wasn’t just okay; it was the miracle cure for everything.
And here’s the thing: For some people, it worked beautifully. Weight loss. Mental clarity. Great energy.
But for others—maybe you—it was a disaster. You felt terrible. Your cholesterol skyrocketed. Your hair fell out. You were exhausted and freezing all the time.
So what’s happening here? If high-fat diets work miracles for some but disasters for others, we’re clearly missing something.
Why Your Friend’s Diet Doesn’t Work for You
Here’s what the diet gurus won’t tell you: Your optimal fat intake depends on YOUR nutrigenomics, YOUR family history, and YOUR current health.
Your Genes Matter (A Lot)
Some people have genes that handle saturated fat (butter, coconut oil, bacon) really well. Others? Their cholesterol shoots up dangerously high on the same diet.
There’s a gene called Apolipoprotein E (APOE) that’s a perfect example:
- Some people (APOE2): Can eat more saturated fat without problems
- Most people (APOE3): Somewhere in the middle
- Other people (APOE4—about 25% of us): See scary cholesterol spikes from too much saturated fat
You and your friend could eat the exact same keto diet. Hers works great. Yours sends your cholesterol through the roof and makes your doctor panic.
Same diet. Totally different results. Because: different genes.
Your Family History Is a Preview
Even without nutrigenomics testing, your family health history tells you a lot.
Ask yourself:
- Does heart disease run in your family?
- Do multiple relatives have high cholesterol?
- Is there a pattern of diabetes?
- Do family members struggle with weight despite eating healthy?
If yes, that high-fat diet everyone’s raving about? Might be risky for you (even if Instagram says otherwise).
Your family tree shows you how your body likely handles different foods.
Your Bloodwork Tells the Real Story
This is where it gets powerful. Your labs show exactly how your body is handling the fats you’re currently eating.
The important numbers:
Cholesterol (but not just “good” vs “bad”): You need to look deeper than basic cholesterol:
- LDL (the “bad” one): But it’s not just about the number—it’s about the SIZE and AMOUNT of particles. You can have “normal” LDL but still be at risk if the particles are small and dense.
- HDL (the “good” one): This protects your heart. Higher is better. (But not too high)
- Triglycerides: High levels (over 100) usually mean your body isn’t handling carbs well or that you may be over-consuming calories from high fat or carb foods.
Inflammation markers:
- CRP (C-reactive protein): Measures inflammation. High CRP means something you’re body is experiencing is making your body angry.
Whether it be illness, infection, stress, medications or even toxin exposure, CRP levels let us know something is going on.
Blood sugar markers:
- Fasting insulin: Shows if your body is resistant to insulin (over 8 is concerning)
- A1C: Your 3-month blood sugar average (over 5.4% suggests problems)
Your labs are your body’s report card. They tell you if your current diet is helping or hurting.
If You Have Thyroid Issues, It’s Even More Complicated
Here’s something the keto crowd doesn’t talk about: if you have hypothyroidism or Hashimoto’s, very low-carb diets can backfire.
Your thyroid might struggle to convert hormones properly without enough carbs. This is why some women go keto and suddenly feel exhausted, cold, and watch their hair fall out and can possibly lead to high cholesterol.
Your thyroid changes the rules for fat intake.
It’s Not Just How Much Fat. It’s Which Fats
Even when you figure out how much fat you need, there’s another piece: which kinds?
The simple breakdown:
Saturated fats (butter, coconut oil, meat):
- Some bodies love these
- Some bodies freak out (cholesterol spikes)
- Your genes and bloodwork tell you which you are
Unsaturated fats (olive oil, avocados, nuts):
- Most people do great with these
- Mediterranean diet evidence is solid
Omega-3s (fatty fish, flax, walnuts):
- Almost everyone needs more of these
- Reduce inflammation
Omega-6s (vegetable oils, processed food):
- Most of us get way too much
- Can increase inflammation
Your optimal mix is unique to you.
Real Examples (Names Changed)
Sarah’s Keto Win:
- Family: Parents healthy, no heart disease
- Started keto: Lost 40 pounds, energy soared, blood sugar normalized
- Labs: Everything improved beautifully
- Her genes handled high fat perfectly
Jessica’s Keto Disaster:
- Family: Dad had heart attack at 54
- Started keto: LDL cholesterol jumped from 130 to 220, felt anxious and exhausted
- Switched to Mediterranean approach: Everything improved
- Later found out she’s APOE4 (doesn’t handle saturated fat well)
- Her genes needed a different approach
Maria’s Low-Fat Backfire:
- Has Hashimoto’s thyroiditis
- Tried 90s-style low-fat: Gained weight, hair fell out, exhaustion got worse
- Added healthy fats back (40% of calories): Thyroid improved, energy returned, felt satisfied for first time in years
- Her thyroid needed adequate healthy fat
Same extremes. Completely different outcomes based on individual biology.
So What Do YOU Need?
Here’s how we figure it out:
Step 1: Know Your Family Story Write down health patterns in your family:
- Heart disease or strokes
- High cholesterol
- Diabetes
- Thyroid problems
- Weight struggles
Step 2: Get Good Testing Not just basic cholesterol. Get:
- Apolipoproteins and Lp(a) panel
- Inflammatory markers (CRP)
- Insulin and blood sugar (fasting insulin, A1C)
- Complete thyroid panel
- Optional: Nutrigenomics testing
Step 3: Look at Your Current Reality
- What are you eating now?
- What do your current labs show?
- How do you feel? (Energy, hunger, mood)
Step 4: Personalize Your Approach
Based on YOUR data:
If you have good nutrigenomics and labs: → You might do great with moderate-to-higher healthy fats
If you have family history of heart disease or concerning cholesterol: → Emphasize unsaturated fats (Mediterranean style), limit saturated fat
If you have insulin resistance: → More healthy fats, fewer refined carbs usually helps
If you have thyroid issues: → Need adequate healthy fats but very low-carb can backfire
This isn’t guessing. This is YOUR body telling you what it needs.
Step 5: Monitor and Adjust Retest in 3 to 6 months. Are things improving or getting worse?
Green lights (keep going):
- Better energy
- Feel satisfied after meals
- Labs improving
- Feel good
Red flags (change something):
- Cholesterol spikes
- Energy crashes
- Hair loss, feeling cold (thyroid warning)
- Can’t sustain it
The Bottom Line
The reason nutrition feels so confusing is because we keep looking for universal rules when your body demands personalization.
The question isn’t “Which diet is right?”
The question is “What does MY body need?”
You can’t answer that by:
- Copying your friend
- Following the latest trend
- Assuming one approach works for everyone
You answer it by:
- Understanding your nutrigenomics blueprint
- Knowing your family patterns
- Testing your current state
- Personalizing based on YOUR data
- Monitoring YOUR response
This is what functional nutrition actually is: using YOUR biology to guide YOUR choices.
If You’re Ready to Stop Guessing
If you’re tired of diet extremes and ready to figure out what YOUR body needs, I can help.
Book your free consultation here where I share more about my methods and approach in Functional Nutritional Therapy and see if Sara Fields Wellness is the right fit for you. From there, we can set up your Intake where the real work starts.
In a Nutritional Therapy Intake, we’ll:
- Review your family health history
- Look at your current symptoms
- Review current diet and lifestyle
- Analyze your bloodwork
- Discuss nutrigenomics testing if appropriate
- Discuss a personalized nutrition approach for YOUR biology
This isn’t about following the latest trend. It’s about understanding YOUR unique body.
Let’s stop guessing about what works for you and find your ideal self.
I work with women throughout Virginia and nationwide via telehealth, specializing in personalized nutrition for thyroid conditions, skin health, gut health, autoimmune conditions and hormonal health.
Sara Fields, Functional Nutritional Therapy Practitioner
Root-Cause Solutions for Radiant Health
Virginia and Nationwide via Telehealth
Quick FAQs
Do I need genetic testing?
Not required but super helpful, especially if you have strong family history of heart disease or confusing responses to diets. We can learn a lot from family history and bloodwork alone.
How much does good testing cost?
Direct-to-consumer labs cost $200-400. 100% worth it to avoid years of guessing what may be going on.
I tried keto and felt terrible. What happened?
Could be several things: thyroid issues, genes that don’t handle saturated fat well, not enough electrolytes, or just not enough carbs for your body. We’d need to look at your specific data.
Can I eat too much healthy fat?
Yes! Even avocado and olive oil are calorie-dense. “Healthy” doesn’t mean unlimited. The right amount depends on YOUR needs.
How long to see if it’s working?
You’ll feel changes (energy, hunger) in 2-4 weeks. Bloodwork changes take at least 8-12 weeks to show up clearly.
I have Hashimoto’s. Should I avoid keto?
Not necessarily avoid, but be careful. Very low-carb can reduce thyroid hormone conversion for some people. Monitor your thyroid function if you try higher-fat approaches.
Related Articles:
- Why Your New Year’s Weight Loss Resolution Keeps Failing
- Your Thyroid Labs Look ‘Normal’ But You’re Exhausted: The 7 Tests Your Doctor Isn’t Running
- Why Personalized Nutrition Is the Future for Women
Disclaimer: This is educational information, not medical advice. Work with your healthcare provider before making dietary changes, especially if you have health conditions or take medications.
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