Why should we get most of our energy from starchy carbohydrates and not sugars?

December 2, 2025 •

4 min read

According to the American Heart Association, most women should consume no more than 25g of added sugar per day. This is because relying on starchy carbohydrates instead of simple sugars provides a more stable, prolonged source of energy, prevents health issues, and supports overall well-being.

Quick Summary

Starchy carbohydrates provide sustained energy due to their slower digestion, unlike sugars which cause rapid blood sugar spikes followed by crashes. Prioritizing complex carbs also supplies essential fiber, vitamins, and minerals, which simple sugars often lack, and helps regulate appetite and manage weight.

Key Points

Sustained Energy: Starchy carbohydrates, unlike simple sugars, release glucose gradually, providing a steady and prolonged energy supply.
Blood Sugar Regulation: Slow-digesting complex carbs prevent rapid blood sugar spikes and crashes, aiding in stable energy levels and better insulin management.
Nutrient-Rich: Whole-food sources of starchy carbs (e.g., whole grains, legumes) offer valuable fiber, vitamins, and minerals that are absent in added sugars.
Weight Management: The fiber in starchy carbs promotes satiety, helping to control appetite and prevent overeating linked to simple sugar intake.
Chronic Disease Risk: Excessive consumption of simple sugars increases the risk of obesity, type 2 diabetes, heart disease, and fatty liver disease.
Informed Choices: Prioritize whole grains, vegetables, and legumes over refined grains and processed foods with added sugar for improved long-term health.

The Fundamental Difference: Digestion Speed

All carbohydrates break down into glucose, the body's primary fuel source. The fundamental difference between starchy carbohydrates and simple sugars lies in their chemical structure and how quickly the body digests them. Simple sugars, known as monosaccharides (like glucose and fructose) and disaccharides (like sucrose), have a simple structure that the body breaks down almost instantly. This leads to a rapid surge in blood sugar and a corresponding spike in insulin. While this provides a short-lived burst of energy, it is often followed by a dramatic crash, leaving you feeling tired and irritable.

Starchy carbohydrates, or complex carbohydrates, are long, complex chains of sugar molecules. This intricate structure means the body takes much longer to break them down into glucose. As a result, glucose is released into the bloodstream gradually and steadily over a longer period. This provides sustained energy without the roller coaster of highs and lows associated with sugar consumption.

The Health Advantages of Complex Carbs

Beyond stable energy, prioritizing starchy carbohydrates offers a multitude of health benefits:

Superior Nutrient Density: Whole-grain starchy foods, vegetables, and legumes are packed with essential vitamins, minerals, and antioxidants that simple, processed sugars lack. For instance, a whole-grain bread contains B vitamins and iron, while white bread has often been stripped of these nutrients during processing.
High Fiber Content: Fiber, a type of complex carbohydrate, is crucial for digestive health. It promotes bowel regularity and helps control cholesterol levels. Fiber is virtually absent in added sugars. Foods like whole grains, beans, and many vegetables are rich in fiber, which can aid in weight management by promoting a feeling of fullness for longer.
Enhanced Weight Management: Because they promote satiety and have a lower glycemic load, complex carbs help control appetite and prevent overeating. Conversely, the rapid crash from simple sugars can trigger cravings for more unhealthy foods, perpetuating a cycle of high calorie intake from nutrient-poor sources.
Better Blood Sugar Regulation: The slow, steady release of glucose from starchy carbs helps maintain balanced blood sugar levels. This is crucial for everyone but especially for individuals with or at risk of type 2 diabetes, as it reduces the risk of insulin resistance.

The Detrimental Effects of Excess Sugar

Conversely, over-reliance on simple sugars is linked to numerous health problems:

Weight Gain and Obesity: Excessive sugar intake, particularly from sweetened beverages, is a major contributor to weight gain and the accumulation of visceral fat. Fructose, a simple sugar, does not curb hunger as effectively as glucose, making it easy to consume an excess of calories.
Increased Risk of Chronic Diseases: High-sugar diets are associated with an increased risk of heart disease, type 2 diabetes, and certain types of cancer. Chronic blood sugar fluctuations and the inflammation they cause are key risk factors.
Fatty Liver Disease: Fructose is processed primarily by the liver. Consuming too much added sugar in the form of fructose can overload the liver and lead to non-alcoholic fatty liver disease (NAFLD).

Comparison of Starchy Carbohydrates and Simple Sugars


Feature	Starchy Carbohydrates (Complex)	Simple Sugars
Chemical Structure	Long, complex chains of sugar molecules.	Short, simple chains of one or two sugar molecules.
Digestion Speed	Slow digestion.	Rapid digestion.
Energy Release	Gradual and sustained energy release.	Rapid energy spike followed by a crash.
Glycemic Impact	Lower glycemic index (GI); causes a slower, lower rise in blood sugar.	Higher glycemic index (GI); causes a rapid, sharp rise in blood sugar.
Nutrient Density	High in fiber, vitamins, and minerals.	Low in nutrients; often 'empty calories'.
Satiety	Promotes a feeling of fullness for longer.	Offers little satiety, leading to more cravings.
Health Impact	Supports stable blood sugar, weight management, and digestive health.	Contributes to weight gain, type 2 diabetes, heart disease, and fatty liver.
Food Sources	Whole grains, vegetables, legumes, potatoes.	Candy, soda, white bread, processed snacks, fruit juice.

Making Healthier Choices

Incorporating healthier, starchy carbohydrates into your diet is a straightforward way to improve your energy and overall health. Here are some actionable tips:

Prioritize Whole Grains: Choose whole-wheat bread, brown rice, and oats over their refined white counterparts.
Embrace Legumes: Integrate beans, lentils, and chickpeas into your meals for a potent dose of fiber and nutrients.
Choose Whole Fruits: Opt for whole fruits instead of fruit juice. The fiber in whole fruit slows sugar absorption and provides more lasting energy.
Add Starchy Vegetables: Incorporate potatoes (with the skin), sweet potatoes, and corn into your meals. Cook them in healthier ways, such as baking or boiling, rather than frying.
Read Labels: Pay close attention to nutrition labels to identify and limit foods with high amounts of added sugars, which can hide in seemingly healthy products.

Conclusion

While both starchy carbohydrates and sugars are sources of energy, their impact on our bodies differs profoundly. By understanding these differences and prioritizing starchy carbohydrates from whole food sources, we can achieve more stable energy levels, better manage our weight, and significantly reduce our risk of developing chronic diseases. Making informed, conscious choices about the types of carbohydrates we consume is a powerful step toward long-term health and vitality. A balanced diet should emphasize nutrient-rich complex carbs, while saving simple sugars for occasional indulgence. The sustained fuel provided by starches is a far better choice for powering our bodies and minds day in and day out.

Visit the CDC for more information on limiting added sugars.

Frequently Asked Questions

The main difference is their chemical structure and digestion speed. Starchy carbs are complex, long chains of sugar molecules that break down slowly, providing sustained energy. Simple sugars are short, simple chains that break down quickly, causing rapid energy spikes and crashes.

Sugars cause a rapid rise in blood glucose, prompting the pancreas to release a large amount of insulin. This excess insulin quickly removes too much glucose from the blood, resulting in a sudden drop in energy levels, known as a 'crash'.

The fiber and slow digestion of starchy carbohydrates help you feel full for longer, reducing overall calorie intake. This contrasts with simple sugars, which provide empty calories and can trigger more cravings.

No. The processing of starchy foods is important. Whole-grain or minimally processed starchy carbs (like brown rice and sweet potatoes) are much healthier than refined starches (like white bread and processed snacks) because they retain more fiber and nutrients.

While sugar intake doesn't directly cause diabetes, excessive consumption can lead to weight gain and insulin resistance, both of which are major risk factors for developing type 2 diabetes.

Good sources include whole grains (oats, brown rice, whole-wheat bread), legumes (beans, lentils, chickpeas), and starchy vegetables (potatoes, corn, sweet potatoes).

Yes, in moderation. Naturally occurring sugars in whole fruits and milk are part of a healthy diet because they come with other vital nutrients. Added sugars found in processed foods should be limited.