In short: a new study of identical twins showed that bad cholesterol (LDL) responds to food largely according to your genes — not just your lifestyle. That doesn’t mean training and diet don’t matter; it means the same menu affects different people differently.
I first read about this in the pages of Muscle & Fitness Hers and it made me think of a friend who eats bacon and eggs every day and goes running once a week — and whose blood tests are flawless. I have to be careful with fat myself. Now it’s clearer why.
Bad cholesterol and genes — what the study actually showed
Lawrence Berkeley National Laboratory and the Children’s Hospital Oakland Research Institute carried out a study published in the American Journal of Clinical Nutrition. It looked at identical twins — the same genetics, but deliberately chosen so that their lifestyles had diverged.
“Although identical twins share exactly the same genes, we chose these twins precisely because their lifestyles were very different,” explained researcher Paul Williams. “One twin in each pair was a regular distance runner; the other rarely ran and trained irregularly.”
For six weeks, the twins followed either a high-fat or a low-fat diet. Every six weeks the diet was switched and their blood cholesterol was measured again. The question was simple: does LDL cholesterol behave similarly or differently in the blood of two people with the same genetics but different lifestyles?
When one responded, so did the other
The result was surprisingly clear. Even though one twin trained regularly and the other hardly at all, their bodies responded to cholesterol almost identically.
“If one of the twins could follow a high-fat diet without the level of bad cholesterol rising, so could the brother,” said Williams. “But if one brother’s LDL cholesterol went up when going on a high-fat diet, the other’s did too.”
In other words: the body’s reaction to dietary fat seems to be written into the genes. One twin couldn’t “erase” with training what the genes had dictated. The other couldn’t “ruin” it with a sedentary lifestyle.
Two types of people — sensitive and insensitive
The study found that some of the twins carried one or more genes that make them very sensitive to dietary fat. Their LDL jumps quickly when the menu contains a lot of saturated fat.
The other group of twins was almost insensitive to dietary fat — no matter how much they trained or didn’t train, no matter how much fat they ate, their LDL cholesterol stayed put.
“Our research showed how important our genes are,” Williams summed up. “Some people have to be very careful about their nutrition, while others have more freedom in their food choices.”
Bad cholesterol in practice — what to do about it
Honestly, this study doesn’t mean that training and diet are pointless. It means that general recommendations — “eat less fat and everyone gets healthier” — don’t apply to everyone equally.
- Have your blood cholesterol level measured — through your family doctor or with a lab panel. One number tells you more than the entire internet combined.
- If your family history includes early heart disease or high cholesterol, you probably belong to the “sensitive” group. Keep saturated fat under control.
- If your LDL is low even with a more relaxed menu, don’t blindly follow rules meant for high-risk people.
- Repeat the test a couple of times a year — your body changes, your weight changes, you get older.
So what actually happens with high LDL? Bad cholesterol accumulates on the inner walls of blood vessels and narrows them over the years. It doesn’t happen in a week or even a year, but in a genetically sensitive person the process can go considerably faster.
FAQ about bad cholesterol
Is bad cholesterol always the fault of food?
No. Genes determine a large part of how the body processes LDL. Diet and training have an effect, but how big that effect is depends on the person.
Can training lower bad cholesterol?
In some people yes, in others not much. Training usually raises “good” HDL cholesterol and improves overall cardiovascular health, regardless of whether your LDL number changes.
How do I know if I belong to the sensitive group?
The simplest way is to measure your LDL before and after a month-long change in your diet. If the reading moves a lot, you’re probably sensitive. Your family history and your family doctor’s assessment help fill in the picture.
Author: https://turg.fitness.ee/et
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