| carbohydrates complex carbs metabolic theory metabolism simple carbs

Are Starches Fattening?

By Tyler Woodward

Are Starches Fattening?


Rice, wheat & potatoes, are they truly the health foods that we've been led to believe? Are these foods contributing to your excess bodyfat? Let me explain...

Key Takeaways:

There’s one rule that we should all know that governs weight loss or weight gain and that is the rule of energy expenditure. Energy balance, also known as calories in. vs calories out. In its simplest form this rule states that:

  • If you consume more calories than you burn you will gain weight
  • If you consume fewer calories than you burn you will lose weight
  • If you consume as many calories as you burn you will maintain your weight

But I’m going to let you in on a little unknown secret…

Not All Calories Are Created Equal

Now, technically speaking this is a lie. Saying one calorie is different than another is the equivalent of saying that one mile is further than another because it was uphill. Miles are a measure of distance, while that mile may be much more difficult to walk or run, the distance is the same. Calories are just a measure of potential energy from food, but how your body utilizes these calories depends on the source. 

Calories In ≄ Calories Out

The source of your calories will affect how your body uses the calories and the number of calories that you burn. We know that whenever you consume an excess of calories your body will store whatever is not burned as fat. The question then becomes what fuel source (macronutrient - carbs, fats or proteins) can we consume the most of 

Your body’s most efficient fuel source is carbohydrates. If you want to read the full breakdown of why your body runs best when on carbs, then make sure to check out my article, “Carbs, Fats Or Proteins | What's The Best Fuel For Your Body”. 

But in short, metabolism can be viewed as your cells ability to breathe. They need to take in oxygen with energy as food to convert it into usable energy and carbon dioxide. While we often think of carbon dioxide as a waste product in breathing/metabolism, it’s actually extremely important in our body. Our cells must give off carbon dioxide in order to absorb oxygen, so the more carbon dioxide our cells produce the more oxygen they can absorb and therefore the more energy they can burn. Respiratory quotient is a useful measurement as a means of measuring your metabolic rate and it is the ratio of oxygen consumed relative to carbon dioxide released.

Respiratory Quotient


Oxygen Consumed : Carbon Dioxide Released




1: .7


1: .8

Carbs are the most efficient fuel source because they release as much carbon dioxide as they produce CO2, encouraging an increased metabolic rate.

Carbohydrates Simplified:


Carbohydrates come in a variety of forms, known as monosaccharides, disaccharides, and polysaccharides. Saccharides meaning sugar and mono, di, and poly referring to the number of sugar molecules 1, 2, and many respectively. 

There are three types of monosaccharides:

  1. Glucose
  2. Fructose
  3. Galactose

When you combine two monosaccharides there are three potential disaccharides:

  1. Sucrose = 1 Fructose + 1 Glucose
  2. Lactose = 1 Galactose + 1 Glucose
  3. Maltose = 1 Glucose +  1 Glucose

Polysaccharides on the other hand are all long chains of glucose molecules. One glucose molecule after another attached together for hundreds of glucose molecules in a row. Polysaccharides all form different shapes depending on their structure and result in two main types:

  1. Structural Molecules - 
    1. Chitin - Animal structural molecule (found in shellfish & insects)
    2. Cellulose - Plant structural molecule
  2. Energy Storage Molecules -
    1. Glycogen - Found mostly in the liver and muscles of animals
    2. Starches - Found in many plants, roots and tubers

All forms carbohydrates will be broken down into glucose with a few exceptions:

  • Cellulose & chitin cannot be digested in humans and will exit the body the same way they enter. 
    • If you’ve ever seen corn kernels or green fibers in your stool, it’s because they cannot be broken down in our digestive system.
  • Fructose has the unique ability that it can be absorbed directly into the liver.

Your body manages its blood sugar levels by releasing insulin. When you consume carbohydrates your pancreas releases insulin, so your cells can absorb glucose to be used as energy.

Read More: Carbohydrates: The Macronutrient Guide

Starches Vs. Sugars:

starches vs sugar

Sugars like those found in fruit, honey and even table sugar are generally made up of both fructose and glucose. This is extremely beneficial from an energy metabolism perspective because fructose does not require the insulin to be released to be absorbed into the cells. Therefore less insulin is required to process the energy from sugar compared to starches which are pure glucose. 

Starches are like driving on a single lane highway. If there are too many cars or an accident occurs, shutting down this lane causes traffic to rapidly build up. Sugars in this regard are a two lane highway. With twice the space to move, much more cars can travel smoothly on the highway without traffic starting to accrue. 

In times of stress, when blood sugar is low, fats are released into the bloodstream. Fat competes with sugars to enter the cell, the more fats in your bloodstream, the harder it is for sugar to enter your cells. If you have chronically elevated levels of free triglycerides or free fatty acids (more fat in your bloodstream) over time this results in insulin resistance through a process known as the randle cycle. Insulin resistance is the phenomenon in which more insulin is required in order to shuttle the same amount of sugar into the cells, basically insulin becomes worse at doing its job.

In the highway analogy, this is like trying to merge two lanes together, resulting in a bottleneck. Both lanes (fat and glucose) are trying to pass through to the other side, but they are met with resistance, ultimately slowing down the entire flow of traffic. This is the worst scenario possible, as your cells aren’t able to get any fuel to be used, either sugar or fats. The best way to combat this is to not allow your blood glucose levels to fall too much by consuming snacks between meals and allowing your liver to heal, to maximize its glycogen stores.

Because starches are made up only of glucose they put a much larger demand on our cells. Remember, our cells require insulin to absorb and use glucose for fuel. If our blood sugar/glucose levels get too high and our cells cannot use/metabolize the glucose at a fast enough pace, then it’s like traffic is starting to accumulate in our cells. In order to clear up this traffic, whatever sugar the cells cannot burn as fuel they are much more likely to store it in order to “clear up the traffic”. This allows your body’s blood sugar levels to get back into a normal range much faster, but it doesn’t ensure that all of this energy is used as fuel.

For example, let’s compare 100 grams of starches (pure glucose) to 100 grams of sucrose (50% fructose & 50% glucose). Because glucose requires the release of insulin to be absorbed into your cells and used as fuel, eating 100 grams of sucrose requires only half the  amount of insulin. The more insulin in your bloodstream, the more “traffic” or “pressure” your cells are under to shuttle glucose into their cells. Additionally, since fructose is absorbed directly into the liver where it is converted into glycogen, this also decreases the amount of sugar in your bloodstream or “traffic”. So yes, starches are technically fattening relative to sugar. 

In reality, while this is true, it is not this black and white. As long as you don’t consume too much of a starch in one sitting then your blood sugar levels will not get too high and your cells won’t be forced to store the glucose as fat. Additionally, very few people consume starches on their own without a fat or protein which influences the time it takes for the starches to be digested and enter the bloodstream. The longer it takes to digest the starches, the more “spread out” the traffic is allowing it to flow through much more efficiently. Lastly, it's important to acknowledge that as long as you are eating at calorie maintenance or in a caloric deficit, you won’t gain weight from eating starches. Even if your body stores some of this glucose as fat it will end up burning this fat (or other fat) later as fuel.

Can You Lose Weight By Eating Sugar?

starches fattening?

I think yes. You now know that sugar is the most efficient source of energy because it allows your body to absorb more oxygen as it releases carbon dioxide. We also know that when your blood gets “backed up” with too much blood sugar that it is more likely to convert the sugar into fat than use it as energy. Sugar, as in sucrose, is much less likely to cause “traffic” to accumulate in your bloodstream because fructose does not increase your blood sugar levels. This allows your cells to not be overwhelmed with excess blood sugar and to burn more calories. So theoretically, you could burn more calories without decreasing the amount of calories you’re consuming. This will over time result in fat loss without consuming less calories, just consuming more sugar relative to fewer starches and fats. 

With this in mind, the next time I attempt to lose weight I will be utilizing this approach to maximize the amount of calories I burn, while maintaining my caloric intake as much as possible. To do this I will swap the majority of starchy foods out for fruits, lower my fat intake, and keep my protein relatively high. My maintenance calories are about 2,500 calories daily, so this will look like:

Total Calories = 2,500

Protein = .82 grams * 200 lbs (current weight) = 164 grams = 656 calories, 

Sugar = ~65% of daily calories. 2500 *.65 =1625 calories = 406 grams

Fat = 2500 (total) - 1625 (carbs) - 656 (proteins) = 219 calories (fat)/ 9= 24 grams fat

Read More: The Sugar Secret

Starches & Digestion:

starches and digestion

Lastly, it’s worth mentioning that relative to sugars many people have issues digesting starches like rice, potatoes or bread. This is because the long chain glucose molecules in starches must be broken down into the single glucose sugars to be used as fuel and enter the bloodstream. The increased time it takes to digest starches can cause issues with the bacteria in our guts which can result in them being fermented and feeding our “bad gut” bacteria. This is why starches should be thoroughly cooked to help break down the starch chain into individual glucose molecules.  But, if you don’t have any issues digesting starches then by all means have at them. 


Sugars are the best bang for your buck because as you know they encourage an increased metabolic rate, meaning we will burn more calories from eating them relative to the other macronutrients. Additionally, because sugar from fruits and honey contain both glucose and fructose they do not increase our blood sugar nearly as much. This allows us to process them most efficiently relative to other foods and makes them the least fattening. While starches are not inherently fattening as long as you are not eating in a calorie surplus, they are more likely to be stored as fat than be burned as fuel compared to sucrose. 

If you want to learn how to eat for optimal health to improve your energy levels, fix your digestion and get rid of your brain fog, then look no further than the Thermo Diet Program. The the Thermo Diet utilizes the Bioenergetic view of health to maximize your energy production, providing your body with the fuel it needs to naturally heal itself. So you wake up and greet the day with the energy levels of your childhood self!

Thermo Diet


My goal in writing this article, as always, is to provide you with logically-based principles that you can use to form your own conclusions regarding any information you may come across within this subject. I really hope you found this article interesting and if you have anything to add to this article, or any comments or criticism, feel free to reach out to me on our facebook groups or on Instagram @tylerwoodward_fit. Also, please feel free to share this article with anyone that might be interested!

Thanks for reading!

Until next time… be good

~Tyler Woodward