|Last update November 12, 2021, article reviewed & updated multiple times since April 20, 2002.|
What You Need to Know
In my last article, I explained the formation of ketone bodies, and we discussed the controversy over ketosis. We learned there are two kinds of ketosis: one, called lipolysis-ketosis, is from normal metabolic processes, and the other, more properly called ketoacidosis, is from disease. We noted that in the absence of preexisting kidney or liver disease, ketosis will not become a problem as long as sufficient and adequate protein and fats are eaten. This is because some of both proteins and fats become glucose, and the presence of glucose in the body prevents too many ketones from forming. The key here is the phrase “in the absence of disease.”
For example, after dietary fat has been absorbed into the body, much of it travels to the liver. But if the liver is not working properly, the fat will arrive faster than the liver can make the ketones. If this happens, the fat accumulates and causes a rather serious condition known by the simple name, fatty liver. The accumulated fat crowds the liver’s blood supply and causes the death of the liver cells. This leads to cirrhosis of the liver. So we can see that the problem is not a high protein diet, a high-fat diet, or even high levels of ketones. The problem is a liver that doesn’t work properly.
In a high carbohydrate diet, the high levels of insulin that are produced favor the storing of fat as adipose tissue, while lessening the liver’s supply of the very fat that would be broken down into ketone bodies and used for energy.
Testing The Effects Of Dietary Fats On DiseaseThere is a rather large difficulty with testing the effects of fats on disease. When researchers reduce the amount of saturated fat in a test diet, they have to give the test subjects something to eat in place of the fats. What they choose to give instead makes a huge difference. Are they adding polyunsaturated fats? Are they adding carbohydrates? What kind of carbohydrates? Are they adding a single carbohydrate or mixed carbohydrates? Are they adding green leafy vegetables or large quantities of pasta?
Each choice of a substitute food for the avoided fats adds a different factor that might alter the outcome. Tests hope to find what changes take place when fats are reduced, but how do we know that the results are actually answering the questions asked?
Food choices can influence the health of entire populations, regardless of whether or not any conscious effort is made to reduce fats and cholesterol. Consider that people who eat large amounts of meat and dairy products, and plenty of saturated fats in the process, tend not to eat a lot of vegetables and/or fruits. Assuming there is a health correlation, is the correlation properly drawn to the high levels of meat and dairy, or should it be drawn to the low levels of vegetables?
We are told of the heart protection offered by the so-called Mediterranean diet. But what is it about this way of eating that makes a difference? Is it the fish, the olive oil, or the fresh vegetables? Or, is it the absence of what people following this diet are not eating, instead of the fish, olive oil, and veggies that they are eating? The general opinion that it is what they eat rather than what they don’t eat that offers the protection, is not supported by the data.
As the Mediterranean nations became more affluent since the 1950s, their people began to eat proportionally more meat and animal fat. Yet, their heart disease rates continued to improve compared to populations that consumed as much animal fat, but ate fewer vegetables throughout the year. Some think there may be heart protection available from fats known as omega-3 fatty acids that are found in fish and green leafy vegetables. There may also be factors in antioxidant compounds such as vitamins and certain trace minerals. It may be that as long as these factors are included, the amount of meat and saturated fats are not important.
So, in the final analysis, no one really knows how to change the diet for maximum success, or if changing the diet makes a true difference, or who will benefit the most, if at all.
Do All Roads Lead to Sugar?Recently, a reader of these pages wrote me to say that her personal trainer had told her that everything we eat turns to sugar. While what he told her is not true, it may seem that way sometimes! As we have discussed in previous articles, 100% of carbohydrates and 65-70% of proteins become glucose (sugar). In the case of dietary fats, about 10% turns to glucose.
When fats are absorbed into the body, the union of glycerol and fatty acids is broken by digestive processes. Some of the glycerol is transported to the liver, where it, like protein, undergoes the change called glyconeogenesis. (This, you will recall, is the formation of sugar from other substances.)
Glycerol has about the same food value as sugar, and follows a similar course when it is utilized by the body. The good news is that dietary fat does not directly produce excess adipose body fat. But the portion that becomes sugar certainly does add to the adipose problem.
As I have previously told you, fats are one of the substances known as lipids. Another member of the lipid group are the waxes. Waxes are not so easily broken down as fats, and they are not digested by the fat-splitting enzymes. Although some waxes may be added to highly processed foods, they are of no value from a nutritional standpoint.
For the most part, waxes are used for industrial purposes such as an ingredient of shoe polish, floor waxes, varnishes, and candles. Beeswax, which is secreted by the honeybee to form the comb, is removed from honey most of the time, since it has no nutritive value to humans, but does have economic uses in industry.
Next time, we’ll talk more about the other kinds of lipids and their place in metabolism. I’ll also have some things to say about cholesterol, which is one of these other kinds of lipids. I hope you’ll join me.
The Science of Low-Carb & Keto Diets
|About Dr. Beth Gruber
Dr. Gruber is a graduate of the Southern California University of Health Sciences and has been in private chiropractic practice in Long Beach, California since 1964. She also received both a Bachelor’s Degree and a Master’s Degree from California State University at Long Beach. She has written on health-related subjects for over 30 years, for several different publications. She lives in Southern California with her husband of 33 years. Both she and her husband follow and live the low-carb lifestyle full time.