The Uncomfortable Truth about Heart Disease, Sugar and Modern Food

For most of our adult lives, we have been told a very simple story about heart disease. Eat too much fat, especially saturated fat, and your cholesterol goes up, your arteries clog and eventually you have a heart attack. It is a neat and persuasive story. It is also incomplete and, in important ways, now outdated.

Much of the original advice to reduce saturated fat came from early observational studies and small trials that linked higher fat intake with raised LDL cholesterol, often referred to as the ‘bad’ cholesterol. From there, fat quietly became the main dietary villain, and low-fat foods were marketed as the healthy choice for decades. Even now, supermarket shelves are still packed with ‘healthier’ fat-free and low-fat options, many of them highly processed and heavily sweetened.

The problem is that when scientists later looked more closely at what actually happened when people cut down on fat, the results were far less impressive than expected. By that stage, however, the idea that fat was bad for us had already become part of everyday thinking, helped along by decades of low-fat marketing and widespread product reformulation.

Large reviews of the evidence have since shown that reducing saturated fat on its own has only a modest effect on cardiovascular outcomes, particularly when fat is replaced with refined carbohydrates such as white bread, breakfast cereals and sugary snacks. In several studies, swapping fat for refined carbs did not reduce heart disease risk at all and, in some cases, led to poorer blood sugar control and higher triglyceride levels.

In other words, it was not simply the fat that mattered. It was what people ate instead.

Dietary cholesterol has also turned out to be far less powerful than we once thought. For most people, eating foods that contain cholesterol, such as eggs or prawns, has only a small effect on blood cholesterol levels. Our bodies regulate cholesterol quite tightly, and much of the cholesterol circulating in our blood is made by the liver rather than absorbed directly from food.

What this means in real life is that blaming butter, eggs and red meat for heart disease has distracted us from more important drivers of risk.

The quality of the overall diet, the amount of sugar and refined carbohydrate consumed, how processed the food is, and how well the body handles blood sugar all appear to matter far more than any single nutrient in isolation.

Cholesterol is not the villain anymore. Metabolic health is.

This does not mean cholesterol is irrelevant. High LDL cholesterol is associated with a higher risk of heart disease, and in some people, particularly those with certain genetic patterns, LDL levels do matter a great deal. But cholesterol on its own tells only a small part of the story.

You can have ‘normal’ cholesterol and still be insulin resistant, inflamed, carrying fat in the liver and quietly developing atherosclerosis. You can also have raised LDL cholesterol and a very low overall cardiometabolic risk because your blood sugar, insulin, triglycerides and inflammation are all well controlled.

This is why many researchers now argue that metabolic health is a far better predictor of cardiovascular risk than cholesterol alone.

Markers that reflect how well the body handles sugar and fat together, such as triglycerides, HDL cholesterol, the triglyceride to HDL ratio, fasting glucose and HbA1c, often track much more closely with real-world heart disease risk than total cholesterol does.

There is also growing interest in apolipoprotein B, or apoB, which reflects the total number of atherogenic particles circulating in the blood. Studies consistently show that apoB predicts cardiovascular events more accurately than LDL cholesterol on its own.

This points to a much bigger and more useful picture…

Heart disease is not simply about fat in the blood. It is about how the whole metabolic system is functioning.

How stable blood sugar is across the day. How much insulin the body needs to produce to keep glucose under control. How much fat the liver is storing. How inflamed the blood vessels are. How much ultra-processed food the diet contains.

If heart disease were discovered today, we would not blame fat.

This is one of the most helpful thought experiments in heart health. If heart disease were being described for the first time today, using the science we now have, it is extremely unlikely that dietary fat would be identified as the main cause.

Instead, the focus would almost certainly fall on a cluster of metabolic problems that appear again and again in people who go on to develop cardiovascular disease.

These include chronically raised blood sugar and insulin levels, fatty liver, high triglycerides, low HDL cholesterol, weight gain around the middle, chronic inflammation and diets dominated by ultra-processed foods.

In other words, heart disease would be seen much more clearly as a condition rooted in metabolic dysfunction rather than a simple problem of eating the wrong type of fat.

This reframing matters because it changes what we actually do to reduce risk.

If fat were the main problem, the solution would be to eat less fat. If metabolic health is the real problem, the solution looks very different.

It becomes about stabilising blood sugar, reducing the burden of ultra-processed food, improving insulin sensitivity, supporting liver health, building muscle, sleeping properly and lowering chronic inflammation.

That is a very different public health message. And if cardiovascular disease runs in your family, it is also a far more hopeful one, because there are many simple and genuinely enjoyable ways to reduce your risk.

Sugar, insulin and ultra-processed food: the real modern drivers

A growing body of research now links cardiovascular disease risk much more strongly to blood sugar dysregulation, insulin resistance and ultra-processed food intake than to dietary fat intake.

Ultra-processed foods add another layer to this problem. These foods are typically high in refined carbohydrates, added sugars, industrial seed oils, emulsifiers and flavourings, while being low in fibre and micronutrients. Large population studies consistently show that higher ultra-processed food consumption is associated with higher risks of heart disease and all-cause mortality.

The mechanisms are likely to include poorer blood sugar control, increased inflammation, changes in the gut bacterial environment, altered lipid metabolism and increased calorie intake without a corresponding increase in satiety.

This does not mean that sugar alone is the new villain. But it does mean that a diet built around refined grains, sugary foods and industrially processed products creates a metabolic environment that is far more hostile to heart health than a diet based on whole foods, natural fats and adequate protein.

But what about lifestyle?

We have known for years that regular movement is good for heart health. Current guidelines suggest aiming for around 2.5 to 5 hours of moderate activity a week, which can include brisk walking, cycling, swimming or anything else that raises the heart rate and leaves you slightly out of breath.

What is now becoming clearer, however, is that long periods of sitting appear to carry their own independent risks, even in people who also exercise.

Recent research suggests that prolonged sedentary time is associated with higher cardiovascular risk, poorer blood sugar control and worse metabolic health, regardless of whether someone meets formal exercise targets. In practical terms, this means that a daily gym session does not fully cancel out the effects of sitting at a desk for eight or nine hours a day.

Regular movement throughout the day, short walking breaks, standing more often and reducing total sitting time all seem to matter for heart health in ways we are only just beginning to fully understand.

And what about sleep?

Most of us know how much better we feel after a good night’s sleep. What is becoming increasingly clear is that sleep is not just about feeling rested. It plays a direct and important role in cardiovascular health.

Poor sleep and chronic sleep deprivation are associated with higher blood pressure, increased inflammation, insulin resistance and greater risk of heart disease. Irregular sleep patterns, not just short sleep duration, also appear to have negative effects on metabolic health and heart rhythm.

In other words, consistently poor-quality sleep acts as a quiet but powerful stressor on the cardiovascular system over time.

What this means for you

When you zoom out from the old fat-versus-cholesterol story and look at the modern evidence, a much clearer and more hopeful picture emerges.

Protecting heart health is not about cutting out butter or obsessing over cholesterol numbers. It is about creating the metabolic conditions in which the heart and blood vessels can thrive.

One of the most consistently supported dietary patterns for heart health is the Mediterranean-style diet. In practical terms, that means:

• Eating mostly real, minimally processed food • Prioritising vegetables, fibre and protein at meals • Choosing carbohydrates for quality, not just quantity, with wholegrain versions over white varieties • Including healthy fats such as olive oil, nuts and seeds, and oily fish • Reducing ultra-processed foods and added sugars

Other supportive measures include:

• Supporting steady blood sugar across the day

• Moving your body regularly, including some resistance training

• Sleeping consistently

• Managing chronic stress and

• Stopping smoking

None of this requires perfection. None of it requires extreme diets or cutting out entire food groups. And none of it requires living a joyless life in pursuit of ‘clean eating’.

What it does require is a gradual shift towards real food, steadier meals, better sleep, more movement and fewer ultra-processed products quietly dominating the diet. Small, consistent changes in these areas compound over time in ways that are genuinely powerful.

And perhaps most importantly, this approach does not just reduce the risk of heart disease. It also tends to improve energy, mood, weight regulation, blood sugar control and overall wellbeing, which makes it far easier to sustain than advice built around fear and restriction.

My invitation to you

If you have been told that your cholesterol, blood pressure or blood sugar are ‘a bit high’, the most useful next step is not panic or drastic dietary overhauls.

It’s curiosity.

Curiosity about how your own body responds to food.Curiosity about how steady your energy and hunger are across the day.Curiosity about whether your meals are really supporting stable blood sugar and metabolic health.

Working with a qualified Health Coach can be incredibly helpful here because personalised guidance makes it much easier to focus on the changes that will actually make the biggest difference for you.

If you’d like a complimentary consultation to see how this could work for you, I invite you warmly to book through my website and let’s start talking https://www.wellhealth.uk/free-consultation

And if you’d like practical ways to begin supporting your heart health through everyday meals, I’ve created a free recipe book with simple, nourishing recipes designed for mid-life health and busy lives.

You can download it here: https://www.wellhealth.uk/heart-health-recipe-book