Why Is Sugar Bad?

December 12, 2011 in Categories: , , , by

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Or maybe this should be titled, “Why Are Carbohydrates Bad?”.  Carbohydrates take the form of either sugars or starches (“complex carbohydrates”); but, a starch is simply a long chain of sugar molecules strung together, so they both end up as the same thing once they enter your blood stream (the only difference is that you need digestive enzymes to break up a starch).  Most carbohydrates break down to approximately half glucose and half fructose (let’s ignore fiber and some of the other less common monosaccharides, for now).  Glucose is then directly used by your cells for energy, whereas fructose must first be converted into glucose or fat by your liver.

Before we go further, let me say that carbohydrates, specifically glucose, are critical for life.  Glucose is energy and your cells need energy to live.  BUT, they don’t need anywhere near the amounts typically consumed in the modern Western diet (often in excess of 500g per day!).  In fact, the high sugar consumption in our diet is the direct cause of the increase in cardiovascular disease, diabetes and obesity seen in the last three decades (since the move toward low-fat, high-starch diets, which we now know are terrible for our health).

How can sugar be both essential and cause disease?  Like so many things, it comes down to dose.  Think of the analogy of alcohol:  a glass of red wine a day can help prevent cardiovascular disease, stroke and even Alzheimer’s disease; whereas a 24oz bottle of scotch a day will destroy your liver and then kill you.  You might think this is a drastic example, but it’s actually a very apt analogy since ethanol is processed by your liver in a very similar way to fructose.  In fact, high fructose intake causes fatty liver disease, which is the precursor to cirrhosis.

The problem comes when a person consumes more sugar than they need for immediate energy usage or large doses of fructose.  When this happens, a cascade of hormones are stimulated so that the extra sugar can be converted into glycogen or fat for storage.  First, the amount of sugar in your blood rises.  This sugar reacts with other components of your blood to produce Advanced Glycation End products, which cause oxidative damage to your tissues and increase inflammation in your body.  High blood sugar can be life threatening and cause permanent brain damage, so your body has a mechanism to deal with this: the hormone insulin.  Insulin helps shuttle glucose into your cells (and when glucose is really high, insulin helps get glucose to into your liver cells to be converted into fat for storage).  When your blood sugar levels are chronically high, your cells can become insulin resistant, leading to more insulin production.  This is what eventually leads to type II diabetes.  Chronically high insulin levels have also been shown to dramatically increase the risk of some cancers.  Some other hormones are stimulated as well, like leptin, a hunger hormone… yes, eating sugar makes you hungrier.

Your liver is responsible for converting excess sugar into glycogen or fat for storage.  But, toxic byproducts (like triglycerides, which are linked to increased risk for heart disease) are produced as part of the conversion of either glucose or fructose into glycogen or fat for storage.  If you consume relatively low carbohydrates, the amount of toxic byproducts is low enough that your body can deal with it easily.  When you consume high levels of carbohydrates, the toxic byproducts build up and contribute to oxidative stress, inflammation, tissue damage and disease.

Most of the cells in your body can easily use fat or ketone bodies (produced by your liver when it breaks down stored body fat) for energy.  The only cells that absolutely need glucose are neural cells.  Although an exact lower limit to glucose consumption is still being debated, there is evidence that a person can survive on as little as 15g of carbohydrates per day.

This doesn’t mean that you have to do a low-carb diet.  When you choose low- and moderate-glycemic load foods (that’s all fruits and vegetables, by the way), blood sugar levels are very well regulated even when carbohydrate intake is very high (upwards of 300g per day).  This is about avoiding added sugars and high glycemic load foods (like grains, refined and processed foods, and junk).  Clinical trials actually show that avoiding high glycemic load foods is far more important than exactly how many grams of carbohydrates you consume.  The American Heart Association now recommends that we consume only five percent of our calories as added sugar (this doesn’t include the sugars in whole fruits and vegetables, for example).

One of the tenants of paleolithic nutrition is to remove all added and refined sugars from our diets and get all of our carbohydrates from whole fruit and vegetable sources.  I would even add that we should focus on consuming large portions of non-starchy vegetables (with more moderate intake of starchy veggies and fruit), which is the ideal situation for liver, kidney and pancreas health.


Just to clarify for some people who have sent me questions… Starchy vegetables and fruit are NOT bad for you and many people include them in their diets with great success (I certainly eat them, but try and keep my serving sizes in check).. Just keep in mind that the carbs add up more quickly when you are eating large quantities of them and that non-starchy vegetables tend to be powerhouses of nutrition.

Good Sugars are they: coconut palm sugar, stevia, agave nectar,Just Like Sugar (chicory root) or are you saying none of the above.

I am gluten free, diary free, oat free, preservative free, refined sugar free.

Could you do an article on why vegetable oils are bad? Your other articles are so informative and easy to understand, I feel like I’m armed with good information after I read them.

you mentioned inflammation twice in this article. Could you explain what exactly is inflammation? I have AS. I have heard that flax seed is good for inflammation, but you’ve mentioned a few times in different blogs trying to avoid seeds. Any thoughts?

Inflammation means cells that belong to the innate immune system are being activated or stimulated to eat stuff. They tend not to be very targetted so they eat healthy tissue along with foreign invaders (like bacteria). In the case if AS, you also have cells that belong to the adaptive immune system producing antibodies that help direct inflammatory cells to attack normal healthy cells in your body. You are also deficient inthe cells that have the job of turning inflammatory cells off.

Flax is billed as anti inflammatory because it contains omega-e fatty acids. However, it it the long chain fatty acids DHA and EPA that are such great antiinflammatories. Flax has a form of omega-3 called ALA which has to be converted into DHA or EPA by or bodies before its useful. That conversion is not very efficient. So, no flax is not particularly useful in resolving inflammation. Good sources of DHA and EPA are primarily fish but also grass-fed and pastured meats.

My body (hands, arms, legs) has ached so much during the past 48 hours because I have been bingeing on sugar and ice cream for a couple of months. Emotional Eater. I haven’t had any alcohol in 18 years. I quit cold turkey because I didn’t want to develop a dependency like my brothers. It’s the ability to not take the first bite and to find a healthy alternative for stress than eating sugar. It’s the hold that sugar has over me when I am upset, anxious, …
What can you tell me about detoxing my system ?
I’m glad I found your site … God bless you …

When I have strong sugar cravings, I eat a spoon of coconut oil. It really helps. Sugar cravings can be both related to neurotransmitters (stress, emotion, etc.) but also from a legitimate need for energy. The coconut oil deals with the energy part (without requiring much from your digestive system) and seems to give me more power to deal with the emotional part.

Hi Mom! gosh I just found your website and im loving it ! what about cane sugar for example lemonade ( I dont like coconut sugar neither stevia for this or honey its just not the same) ? can I use this sparguinly?

Hi Paleo Mom! Just saw a post from someone below that said you know a lot about the gut problems because you healed your own gut. It took me 2 years to figure out what was wrong with me and I finally figured it out when I came across ” Leaky Gut Syndrome ” on the Internet while searching. So I have been doing EVERYTHING for 3 months now. But , I learned how BUTYRIC Acid heals the gut so I started eating green banana and coconut milk smoothies every day. 1/4 cup green banana 3 tablespoons organic coconut milk and a little water and organic stevia. The good gut bugs apparently like to eat the resistant starch in the green bananas?.. Then I read that you could buy BUTYRIC Acid online so I bought some. Then I thought that it would be better/ faster to dissolve the BUTYRIC acid ipill in a few cups of distilled water and use it as an enema. After I did it at night, the next morning I woke up and VOILA! The inflammation in my feet was reduced by probably 80%!!! So I have been doing the BUTYRIC acid enema once a week and it has been helping rid my body of intense inflammation more and more. I’m hoping to heal the gut lining and I also mix in a super potent probiotic as well. It’s the first time in about 10 years that something has helped with pain in my feet especially, and other inflammation in my body. Of course I have been on the Paleo way of eating for 2 years and even ate very healthy before that. So I was just wondering what you think of the BUTYRIC acid enemas? Also wanted to post this for anyone that has suffered from terrible inflammation like myself. Maybe this info will help them. No doctor was ever able to tell me WHY I have such bad inflammation. I basically took antibiotics about 3-4 times a year starting at 8 years old and they destroyed my gut and caused a lifetime of side effects. I’m only 51 and although I look healthy, I have juvenile diabetes, calcified arteries, 4 stents, 15 root canals, and tons of dental work from trying to save my teeth, ADD, Brain fog, sinus infections, urinary tract infections, teeth infections, and you name it, I have it! I took incredibly good care of my body all my life and now I know what caused all the problems. So now that I know, I’m doing everything I can possibly do to heal and seal my gut so that hopefully I can live a Normal life afterward. I also haven’t been able to go to the bathroom without taking laxatives for 30 years now. So hoping that healing my gut will alleviate that problem as well. I’m feeling Happier than ever since using the BUTYRIC acid, and so I know it is working. Sorry this is so much info but again I hope it helps other people. Love your blog and you have incredibly awesome information about all this gut stuff!

Hi Doc. I was wondering, when you write glycemic load, do you mean glycemic index? In this paragraph “When you choose low- and moderate-glycemic load foods (that’s all fruits and vegetables, by the way), blood sugar levels are very well regulated even when carbohydrate intake is very high (upwards of 300g per day). This is about avoiding added sugars and high glycemic load foods (like grains, refined and processed foods, and junk). Clinical trials actually show that avoiding high glycemic load foods is far more important than exactly how many grams of carbohydrates you consume.” when you say upwards of 300 grams daily, THAT’s the glycemic load isn’t it? Isn’t the word “load” referring to the AMOUNT of carbohydrates consumed? Wouldn’t it be fair to say that the problems occur when you eat high glycemic INDEX foods? As I understand this, it’s safe to consume “lots” (high loads) of low glycemic index foods like fresh whole fruits and veggies and problematic to consume even small amounts (low loads) of high glycemic index foods such as refined sugars, grains and such…? So the problems don’t really relate to glycemic loads, but rather to glycemic index? Or am I completely confused 🙂

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I just would like to add a correction to this sentence part “let me say that carbohydrates, specifically glucose, are critical for life” (start if second paragraph. Glucose is not required for life at all. If you look at Nordic tribes such as the American Eskimos, and in other countries still living tribes, they live off of whale or walrus blabber all year long. There is no glucose in anything they eat. Sea food is rich in potassium, magnesium, calcium, sodium and a few other minerals our body needs. Some of the organs they eat raw to get the C they need (cooking would kill C). They have perfect nutrition without any carbs. The modern Ketogenic diet interpretation of this no-carbs diet is modified to include some carbs because our food does not contain nearly as much or enough fat as what we need and what these Nordic tribes live off of. They also restrict protein because protein turns into glucose via gluconeogenesis and that is harmful if gone unchecked. These tribes feed lean meat to their dogs.

The human body is perfectly capable to live off of such high fat low protein and zero carbs diet provided it is turned over to fat-burning (ketones) instead of carbs burning (glucose) mechanism. Fat burning diets exists and are used for a variety of health conditions and also for weight loss. The only reason we thing in terms of “glucose is essential” because everything we can purchase that is commercially available to us has glucose in it and because there is not enough money in selling fatty meats and tons of fat. There is much more money and more sexy to stamp a label of “diet food” on a glucose initiated (dextrose) diet food causing diabetes in the process that also feeds the medical and pharmaceutical industries.

True healthy human food should not include any grains (yep, no cereals or breads or pastas or even rice), no low fat anything, no glucose anything (not even fruits if we don’t want to). We can have carbs with minimal glucose in green non-starch vegetables and even at that, controlling the amount of carbs is hard… they are just too high.

Our cells do much better without any glucose whatsoever by burning ketones. Few people have the discipline to be on such restrictive diets becuase we are surrounded by b-day cakes and wedding cakes and the most fashionable frozen yogurt (which, by the way, if you put a cup of in your fridge to melt, will melt down to 2 tablespoons of sugar water. No yogurt in that at all. Too many people are misinformed. Glucose is an “option” and is not required.

Angela A. Stanton, Ph.D.

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