There has been a lot of debate recently in the blog world about the reasons people become obese. The high-carbohydrate-high insulin theory and/or the food reward/palatability theory seem to be the latest topics among some food bloggers? In essence, does it really matter? We are what are – an obese society in the U.S. and now globally – probably due to a complex interrelationship between genetics, physiology, and the environment.
In the meantime, there is little discussion on how diets affect our heart health as measured by their effects on blood lipid levels. We have had a vast amount of research on how fats effect cholesterol; however, less attention has been paid on how low-carb diets affect blood lipids. Since I have recently been leaning toward a lower carbohydrate diet, I researched the effects of a low carbohydrate diet on cholesterol and triglyceride levels in the blood.
I decided about a year ago to experiment a little with a low carbohydrate diet. The results were that a low-carbohydrate diet significantly lowered my triglyceride levels (which were tending to be high) and raised my healthy HDL levels to a number slightly above the high acceptable range of 89 (based on lab results). Wow! This has been shown in two consecutive lab results over the last year. This does prove anything, except that I have seen benefits that certainly may not occur in everyone.
So what does the science say? The two main effects of a lower carbohydrate diet appear to be with triglycerides and HDL-cholesterol (the so-called healthy type).
Triglycerides are the form in which the body stores fat and a high level is a risk factor for heart disease and stroke. Lots of studies have shown us that low-carbohydrate diets are effective in lowering these blood levels and the results are quite dramatic and consistent (as was shown in my personal experience).
High density lipoprotein cholesterol (HDL) appears to be heart protective and is thought to be a risk factor for heart disease when levels are low. So when a diet raises these levels to a healthy range, this is good. Again, this happened to me.
Almost all nutrition research is controversial, but from what we think now, high LDL-cholesterol is “bad “ in terms of heart disease risk. Some studies show that low-carb diets increase LDL-C and other studies show no effect or slightly reduce it.
A more recent approach indicates that the particle size is important when it comes to LDL. Small particle size equals an increased risk for heart disease whereas; a larger particle size lowers the risk. The thinking is that the smaller size may lodge in the walls of blood vessels more easily – but this thinking to me seems very simplistic and certainly requires more investigation.
Studies have consistently shown that a low-carb diet increases LDL particle size and that higher-carb diets seem to produce a greater percentage of smaller cholesterol particles in some people.
The Bottom Line: There is much individual variation in diet effects on disease risks more than likely due to genetics and many other factors. Weight loss also confers health benefits, so the question becomes whether the beneficial results of a low-carb diet is due to weight loss or carbohydrates alone. Some studies have indicated that a low-carbohydrate diet has a beneficial effect on blood lipids even without weight loss. In my case, weight loss was not involved. But until science sorts it all out, I personally will stick with a lower carbohydrate intake due to my personal lab results.
We often forget about the health benefits of diets and only concentrate on weight loss. In my case for now, low-carbohydrate rules.