by Robert Santana, PhD, RD, SSC | December 07, 2022

coarse sugar in a bowl

Over the last twenty years, no nutrient has been villainized more than “sugar.” This largely started with the booming popularity of the Atkins Diet in the late 90s/early 00s, and morphed into various other fad diets in the years that followed. Today it is called “keto” – tomorrow it will be called Something Else. Prior to this, fat was the demonic monster hiding in our food, however, it never experienced the constant resurgence in notoriety that carbohydrates and “sugar” have over the last several decades.

My theory is that this is simply due to the practical implications of restricting fat versus restricting carbohydrates. It is far easier to remove potatoes from a plate than to remove intramuscular fat from a steak or the butter used to prepare it. However, it must be said that virtually all morbidly obese people got that way through the undisciplined over-consumption of sugar, not fat. The boom of the convenience food market has led to the mass production of “snack foods” that are often high in sugar, fat, or both. Sugar sweetened sodas, juices, and other beverages along with high fat/high sugar “sweets” are the most common. Interestingly, consuming high fat/high sugar foods (i.e. Oreos, pies, ice cream etc.) overrides satiety signals, allowing for extreme consumption. This is not sugar's fault nor are many of these foods “pure sugar” or “pure carbohydrate.” Sugar, when consumed appropriately, accounts for a large and important part of the healthy diet for people who train seriously.

It is important to understand that “sugar” is a broad term that can apply to all carbohydrates. There are many ways to categorize carbohydrates, and I find that the “simple” versus “complex” classification system, when clearly defined, is sufficient for the purposes of differentiating carbohydrate sources. “Simple” carbohydrates refer to those consisting of 1-2 sugar molecules bound to each other and “complex” carbohydrates refer to those consisting of “many sugars” bound to each other. For our purposes, we will refer to carbohydrate sources with more than 2 sugars as “complex” carbohydrates. Since this article is not a deep dive into biochemistry, a table of sugar classifications is included below. The list of major food sources is not all inclusive and some of these sugars can be found in multiple foods (e.g. beans contain both assimilable and non-assimilable polysaccharides). You can find the additional biochemical details in my Carbohydrates and Barbell Training article.   

Simple Carbohydrates


Major Food Sources

Monosaccharides (“one sugar”)


Honey, dextrose powder


Fruits and fruit juice


Beetroot, gums, and mucilages

Disaccharides (“two sugars)

Sucrose (Glucose + Fructose)

Table/Cane sugar, beetroot, honey, some fruits, sweetened beverages such as soda, juices, and sweetened coffee beverages, most candy.

Lactose (Glucose + Galactose)

Milk and dairy products

Maltose (Glucose + Glucose)

Malted beverages

Complex Carbohydrates

ExamplesMajor Food Sources

Assimilable Polysaccharides (“many sugars”)

Starch, Amylose, Amylopectin

Rice, pasta, cereals, pulses, beans and legumes, and starchy vegetables such as potatoes, corn, butternut squash, and peas.

Non-Assimilable Polysaccharides

Cellulose, hemicellulose, pectins, mucilages, gums

Non-starchy vegetables such as peppers, onions, kale, mushrooms, cucumbers, etc.

The anti-sugar propaganda of the last 20 years has confused a lot of people on this topic. Again, all carbohydrates are comprised of sugars, and there are multiple sugars in the human diet, all of which have different chemical properties and some of which undergo different metabolic and digestive processes in the body. None of them are “bad” – they are just needed more sometimes versus others, such as proximal to higher levels of activity. “Added sugar” means they added sucrose in addition to whatever was naturally occurring in the item. Some foods have “high fructose corn syrup” added, which contains 5% more fructose than sucrose. They are both simple sugars and it is unclear that high fructose corn syrup is worse than sucrose, which is recommended in small amounts anyways. There is a time and place for consuming sucrose, and it’s not always a bad idea.

In general, consume “sugar” during or after the workout window when your body needs the carbohydrates quickly (i.e. after an overnight fast or immediately after a training session). Sucrose is metabolized faster than fructose, lactose, starch, and glycogen – the reason it is a decent source of carbohydrates around high levels of activity. However, sucrose is 50% fructose, so it isn’t quite as good as pure dextrose (another name for glucose). Fructose metabolizes slower because it is metabolized entirely in the liver. That’s why the anti-fruit people are silly to say “fruit is bad because fruit is all sugar.” Fruits are mostly water, fiber, and fructose, which result in slow digestion and absorption. They also contain many important micronutrients, making them a good addition to a well-balanced diet.

Rapidly digesting sugars can be productive for someone engaging in vigorous activity. As a general rule, the more intense the activity the more carbohydrates are needed. A marathon runner will require a large quantity due to the repetitive muscle contractions that take place over a hard-run 26-mile race. A lifter may not need as much, but that does not mean that “keto” is appropriate either. There are several important reasons for keeping carbohydrate intake at a moderate-to-high level for a lifter. Although a set of five squats is relatively quick in relation to an endurance event, multiple sets, performed across multiple exercises will break down some muscle glycogen throughout the length of the training session.

Second, people who train first thing in the morning are coming off an overnight fast. This means that liver glycogen stores are low, blood glucose levels are low, and the lifter is not fully hydrated. Taking in carbohydrates, fluid, and electrolytes before and/or during a morning workout can reduce the risk of training with low blood glucose levels, low blood pressure, and mild dehydration, all of which can interfere with training performance. Many of those who train in the morning experience dizziness, fogginess, and low energy levels. The same applies to those who train after a long fast during the day, or those who are dieting and under-eating by design.

If you prefer to eat a meal, a breakfast sandwich on white bread with an orange or banana can be a good pre-workout meal. If eating a full meal has your stomach barking at you, then perhaps a dextrose and protein shake with a ¼ tsp of reduced-sodium salt is a cheap and easy way to consume rapidly digesting carbohydrates, fluid, and electrolytes. Lastly, if all else fails there are plenty of expensive sport drinks to choose from as well.

Again, for people who train, all this “sugar” nonsense has been taken completely out of context. Use common sense, avoid candy/soda/added sugar/etc. and stick to naturally occurring carbohydrate sources, and you will live a nice long life, hit your PRs, and not piss off your friends when they want to go out for a milkshake after a hard training session.    

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