Home » Beware the Low Fat, High Carbohydrate Diet How fats, carbohydrates and proteins may affect your blood sugar and general health

Beware the Low Fat, High Carbohydrate Diet How fats, carbohydrates and proteins may affect your blood sugar and general health

Some people have gone overboard with the low fat concept, especially women watching their weight.  Fat calories slow the flood of carbohydrates into the blood, which helps to eliminate “sugar highs” as well as the corresponding crash after the glucose is burned off.   Athletes improve their performance and diabetics become healthier when they switch to a diet higher in certain kinds of fat and protein and lower in calories. In addition, there are certain fatty acids which we require for optimal health which can only be found in certain foods.  And some researchers believe that people with type-O blood may be more likely than others to thrive on a diet rich in protein and fat and low in grains and dairy products because they trace their genes back to hunter-gatherer societies.

Please note that I am NOT talking about a high-protein “Atkins” type of diet in this article! Instead, I’m concerned about people who are nearly eliminating all fat and protein from their diet, so that they are eating 90% carbohydrates.


“I have also noticed with great concern how hyperactivity among both children and adults has escalated into a new condition called Attention Deficit Hyperactivity Disorder since we have all been cutting out fat and upping the carbohydrates.  The lack of mental focus and inability to sit still among the ADHD individuals could well be due to a lack of blood sugar…” – Ann Louis Gittleman, M.S., C.N.S., one of America’s leading nutritionists, from “The 40-30-30 Phenomenon.”


I don’t believe that high carbohydrate diets are causing ADD, but I do feel that some ADDers may be especially sensitive to high insulin levels generated by the modern low fat diet. It is hard to get young children to eat well, and most prepared food marketed for children is low in fat and high in carbohydrates, so this may be a factor worth considering.

The Problem With Eating Lots of Carbohydrates
Conventional wisdom says that we should get most of our calories from complex carbohydrates and eat just enough protein to get by.  Fats have been nearly eliminated in most processed foods these days, and the fats that are included are unhealthy types of fats like trans-fats and most vegetable oils. Could this be part of our problem? Are we  striving for a diet which is unnatural and not so healthy as we think?   Fats supply two types of required fatty acids that our bodies cannot manufacture. These fats are GOOD.  See my page “Fatty Acid Deficiencies are Epidemic” for more info.

What could be wrong with eating lots of grains?  Even though they are complex carbohydrates, most grain products are digested very rapidly and enter the blood stream as sugars almost immediately after you eat them. This includes whole wheat bread.  The body experiences a sharp spike in blood sugar and releases a corresponding amount of insulin in response.  High insulin is bad.  Insulin decreases the sugar in your blood and in your brain.  Low sugar in the brain means poor concentration, fatigue, and other problems.  Insulin also is responsible for turning blood sugar into body fat so you gain weight even as your energy decreases, and insulin is also linked to the serotonin system which regulates mood.

The medical term for high insulin levels is “reactive hypoglycemia” and I was diagnosed with it in my early twenties.  At times my sugar would drop so low that my hands and legs became shaky, I could barely think, I was incredibly thirsty, flushed, and could think about nothing else but eating sugar.  All I had to do was eat one piece of candy and I’d be fine in five minutes. Of course this would only cause a repeat of the cycle.  At the time, I was told to avoid sugars.  No one ever told me that many complex carbohydrates are just as bad as sugars, so I only got worse over the years.   Later I developed gestational diabetes.

ADDers are known for being caffeine/sugar junkies.  I was.  The sudden surge in caffeine and sugar increases brain activity and focus.  The tradeoff, however, is the crash that follows as well as an increased tendency to become hypoglycemic. To avoid the crash, we junkies keep eating more carbohydrates and drinking coffee.  This results in a perpetually high insulin level which stresses the system.

A diet high in complex carbohydrates and low in fat can lead to chronic hypoglycemia, and a person can develop “insulin resistance”  where insulin no longer seems to work as well as it used to, and finally diabetes, in which the pancreas ceases to release insulin at all. I was shocked to discover that grains and many fruits and vegetables that I ate a lot of have a very high “glycemic index,” which means their energy enters the blood stream rapidly.   An estimated 25% of the population is believed to be insulin resistant to some degree, and some researchers believe the number may be as high as 75%.

Here are how some foods rank in terms of how they affect insulin levels. Low inducers are best, however, high inducers can be eaten if a fat is also eaten at the same time since the fat binds to the carbohydrates and slows absorption.  For example, you could eat carrots (bad glycemic index) in a salad with olive oil.

Rapid inducers of insulin (bad): glucose, puffed rice, corn flakes, bran flakes, white and whole wheat bread, carrots, apricots, honey, brown rice, potato, banana, kidney beans, wheat.

Moderate inducers of insulin: raisins, spaghetti, pinto beans, macaroni, rye (pumpernickel), applesauce, potato chips, lactose (milk sugar), peas, yam, sucrose, grapes, oranges, orange juice.

Low inducers of insulin (good): apples, pears, tomato soup, ice cream, chickpeas, milk, yogurt, fish sticks, lentils, fructose, plums, peaches, grapefruit, cherries, soybeans, peanuts.

I bet you’re surprised. 

I now try (emphasis on try) to follow alternative dietary guidelines called the “40-30-30”  or “Zone” diet, which consists of 40% carbohydrate calories and 30% each of protein and fat calories. Each meal must have the proper balance. My previous diet since childhood was about 85% carbohydrates, so this was a monumental shift in the way I ate.  Within a few days I noted one very dramatic result: My intense food cravings had ceased.  I immediately started losing weight because I could finally resist the urge to snack.   In six weeks I lost 20 lbs, which I’d been trying to do for years.

How can you tell if high insulin levels and low blood sugar are a problem for you?     Here are some symptoms:

1. Failing to lose weight while sticking to a low-fat, high carbohydrate diet.
2. Mid-morning or mid-afternoon drops in energy, a few hours after eating.
3. Sugar cravings.
4. Bloating or water retention
5. Fatigue after exersizing
6. The more carbs you eat, the more you want.
7. High cholesteral, high triglylcerides, high blood pressure or diabetes.

zone.gif (3895 bytes)The 40-30-30 or “Zone” diet was invented and popularized by Barry Sears, Ph.D.,  in the 1995 book “The Zone.”  There are numerous reader reviews at in which people say they lost weight, increased their athletic performance, lower their blood sugar and/or reduced their cholesteral after following the diet. Foods are now sold at my local supermarket which are marketed for the 40-30-30 diet, including a drink called “Balance” which I have for breakfast every morning. 


How our ancestors ate: Are you a Hunter?

If you’ve followed the “Hunter in a Farmer’s World” concept popularized by Thom Hartmann, you know that humans evolved for millions of years as hunter/gatherers and only about 20,000 years as farmers.  Just as our “attentional” needs may reflect our hunter ancestry, so too may our nutritional needs.  Up until 20,000 years ago people ate lots of meat and whatever roots and berries they could find.  It makes sense that people may thrive on a diet which most closely resembles the diet we evolved with.

However, it appears that all people are not the same.  According to one theory, the four blood types can be correlated to the agricultural revolution and the changing metabolic requirements that eating grains entailed.  Type O blood was the original hunter-gatherer blood-type and is the most common blood type in America today.   People with Type O blood may not do well with dairy products, grains, and legumes.   I am a Type O, and this describes me perfectly.

People with Type A blood thrive on a vegetarian diet but have trouble with dairy products.  It is believed that this blood type emerged between 25,000 and 15,000 B.C. in response to the agricultural revolution.

People with Type B blood digest most foods quite well.  This blood type is thought to have emerged between 15,000 and 10,000 B.C. in the Himalayas and later expanded across the Eurasian plains via nomadic peoples.

Those with Type AB blood are like Type A except they have no problems eating diary products.  This is the newest blood type, which appear to have evolve about 1000 years ago.


The Zone, by Barry Sears, Ph.D.

Beyond Prozac: Brain-Toxic Lifestyles, Natural Antidotes & New Generation Antidepressants by Michael J. Norden, M.D

The 40-30-30 Phenomenon by Ann Louise Gittleman, M.S., C.N.S, author of Beyond Pritikin.