Health | Cholesterol
How do I Eat Fats While Staying Healthy?
Is Cholesterol Really The Problem…
How Did People Come Up With “Saturated Fat Causes Heart Disease”?
The Origin of a Hypothesis
In the mid-20th century, American physiologist Ancel Keys changed how the world viewed dietary fat.
His famous Seven Countries Study popularised the idea that saturated fat was a primary cause of cardiovascular disease, which became one of the most influential nutrition narratives of the last century.
Questioning the Dogma
For decades, the fact that saturated fat increases LDL(bad) cholesterol was treated as the norm. Even doctors, clinicians, public health guidelines, and the media repeated it without questioning its legitimacy.
However, when a researcher, Fred Kumo, warned about the dangers of industrial cooking oils and trans fats, few believed his claim. Decades later, trans fats were restricted in many countries for being harmful.
The lesson? Even the most established nutritional “truths” must be challenged when new evidence emerges.
Cholesterol vs. Fat: Not the Same Thing
Many people mix up cholesterol and fat together, but they are very different molecules.
Cholesterol is a complex, ring-shaped fat found in every cell, which is essential for survival. Its main roles include:
- Maintains cell membrane fluidity for proper cell functions.
- Serves as the building block for key hormones such as oestrogen, progesterone, testosterone, and cortisol.
- Forms bile salts, which break down dietary fat.
- Vitamin D synthesis.
Main Types of Cholesterol in Blood:
Cholesterol is hydrophobic (water-hating), meaning it cannot travel freely in blood. Therefore, it requires specific carriers, Lipoproteins, to move around the body.
1. LDL (Low-Density Lipoprotein) — “Bad cholesterol”
- Carries cholesterol from the liver to tissues.
- Excess can deposit in artery walls, leading to plaque buildup (atherosclerosis).
2. HDL (High-Density Lipoprotein) — “Good cholesterol”
- Transports cholesterol from tissues back to the liver for disposal.
- Protective against heart disease.
3. VLDL (Very-Low-Density Lipoprotein)
- Primarily carries triglycerides from the liver to tissues.
- Eventually turns into LDL after losing triglycerides.
4. IDL (Intermediate-Density Lipoprotein)
- Transitional form between VLDL and LDL.
- Short-lived in the bloodstream.
5. Chylomicrons
- Transport dietary fats and cholesterol from the intestines to tissues after meals.
On the other hand, dietary fats are your body’s energy source.
Fats are a concentrated source of energy and are essential for nutrient absorption, hormone production, and cell health. They come in several main types:
Saturated fats
- Found in processed foods like sausages and chips.
- In excess, they can raise LDL cholesterol in some people.
Trans fats
- Often industrially hydrogenated (partially solidified) and linked to a higher risk of heart disease.
- These should be avoided as much as possible.
Monounsaturated fats (MUFAs)
- Found in olive oil, avocados, and certain nuts.
- They can improve heart health and support healthy cholesterol levels.
Polyunsaturated fats (PUFAs)
- Found in nuts, seeds, and some plant oils, which can significantly lower LDL (“bad”) cholesterol by improving how the liver clears it from the blood.
- This group includes omega-3 and omega-6 fatty acids, both of which are essential in small, balanced amounts.
How Saturated Fat Affects Cholesterol
For most people, dietary cholesterol (like the cholesterol in eggs) has little effect on blood cholesterol.
The body balances what it absorbs and produces, so eating a couple of eggs a day won’t usually spike your cholesterol.
Saturated fat, however, is a different story. It can raise LDL (“bad”) cholesterol in many people.
Get Charlotte Wong’s stories in your inbox
Join Medium for free to get updates from this writer.
The old idea that “saturated fat causes high cholesterol, which leads to heart disease” is now seen as too simplistic, but there’s truth in part of it:
- Large amounts of saturated fat often increase LDL cholesterol.
- The effect is most concerning when paired with excess calories and poor diet quality, not in moderate, balanced eating.
The Seeds Oil Debate — And How To Choose Healthy Fats
Choose minimally processed, whole food fats:
- Extra virgin olive oil
- Grass-fed butter (in moderation)
- Coconut oil
- Avocados
- Nuts and seeds (without added flavour)
Concerns About Seed Oils
Seed oils (such as soybean, sunflower, corn, and canola) have stirred debate. Critics point to:
- Omega-6 Imbalance: Many seed oils have a high omega-6 to omega-3 fatty acids ratio, which may promote chronic inflammation.
- Industrial Processing: Seed oils often come from GMO crops treated with chemical solvents, then deodorised and bleached, making them far from “natural.”
- Oxidation Risk: These oils are easily oxidised, potentially creating harmful compounds during storage or high-temperature cooking.
How Carbohydrates Impact Cholesterol
Refined carbohydrates
- Food like white bread, white rice, sugary snacks, and ultra-processed products can worsen cholesterol profiles.
- Excess refined carbs are quickly absorbed, raising blood glucose and prompting the liver to convert them into triglycerides.
- These triglycerides are packaged into lipoproteins containing ApoB and increase LDL cholesterol.
Whole grains and fibre
- Soluble fibres, such as beta-glucans found in oats, legumes, and beans, bind cholesterol and bile acids in the gut and help lower blood cholesterol levels.
- Insoluble fibres act as prebiotics, improving gut microbiome diversity, which influences liver metabolism, and indirectly lowers cholesterol synthesis into the liver and the blood.
Other Factors Affecting Cholesterol
Cholesterol levels are influenced by more than just diet. Several additional factors play a crucial role:
1. Genetics
- Conditions like familial hypercholesterolemia and variations in LDL receptor efficiency can significantly impact cholesterol regulation.
2. Lifestyle
- Excessive alcohol consumption, obesity, and physical inactivity can all negatively affect cholesterol balance.
3. Gut Microbiome
- Certain gut bacteria are linked to higher HDL and lower LDL cholesterol.
- Supporting the microbiome through fibre-rich foods and probiotics can be beneficial.
4. Menopause
- LDL cholesterol can rise by around 25% during menopause due to the loss of oestrogen, which reduces LDL receptor activity.
- Dietary and lifestyle interventions become especially important at this stage.
Actionable Dietary Advice for Managing Cholesterol
Managing cholesterol doesn’t have to be complicated. Small, evidence-based changes to your daily eating habits can make a big difference.
1. Don’t Fear Healthy Fats
- If you’ve been told to go on a very low-fat diet for cholesterol, think again.
- Research shows that moderate fat intake from healthy sources is far more effective than cutting fat altogether.
2. Prioritise Polyunsaturated Fats
- Nuts, seeds, and plant-based oils (like flaxseed or sunflower oil) are rich in polyunsaturated fatty acids (PUFAs).
- These fats enhance LDL receptor activity in the liver, helping your body clear “bad” cholesterol from the blood.
3. Limit Refined Carbohydrates
- White bread, white rice, sugar, and ultra-processed foods may raise triglycerides and worsen cholesterol levels.
- Cutting back helps stabilise blood sugar and reduce the production of harmful lipoproteins.
4. Load Up on Fibre and Whole Grains
- Soluble fibre from foods like oats, beans, lentils, and pulses binds cholesterol in the gut and lowers its absorption.
- Insoluble fibre improves your gut microbiome, which indirectly supports healthier cholesterol metabolism.
5. Rethink “Low-Fat” Products
- Many so-called low-fat foods are loaded with sugar or refined starches, both of which can negatively impact cholesterol.
- Whole, minimally processed foods are a much better choice.
6. Expect Results in Weeks, Not Years
- The good news: measurable changes can happen in just 10 days.
- With consistency, one to two months of dietary improvements can deliver significant cholesterol benefits.
7. Lifestyle First, Medications Second
- Statins are powerful and effective for those with very high cholesterol or a strong genetic risk.
- But for many people, diet and lifestyle should be the first line of defence, and often work surprisingly well.
Conclusions
Our understanding of cholesterol and dietary fat has come a long way. The old idea that “all fat is bad” or that eating cholesterol directly raises blood cholesterol is outdated.
Today, the focus is on:
- Choosing high-quality fats (like olive oil, nuts, fatty fish, and whole plant foods).
- Avoiding refined carbohydrates and ultra-processed foods.
- Supporting natural cholesterol regulation through diet, lifestyle, and gut health.
Ultimately, it’s not just about cholesterol levels at a single moment, but how long LDL cholesterol stays elevated over your lifetime that shapes cardiovascular disease risk.
Discover more lifestyle hacks on my Gumroad.
Thank you for your support!
