Low NSC Horse Feed: Does Your Horse Really Need It?

Not all calories are created equal when it comes to your horse’s feed. The amount of sugar and starch—known as NSCs—in the horse's diet can make a significant difference in their overall health and performance.

Knowing when a low or very low NSC feed is necessary—and when a different type of feed makes more sense—can help support your horse’s long-term well-being.

What NSC Means—And Why It’s Important in Your Horse’s Diet

In recent years, non-structural carbohydrates (NSC) have become one of the most talked-about topics in equine nutrition.

The term NSC refers to the total amount of sugars and starches in a horse's feed. Forages like hay and pasture grass also contribute varying levels of NSC depending on growing conditions. 

When digested, carbohydrates are broken down in the small intestine into glucose, which enters the bloodstream and fuels the body’s cells. The hormone insulin then helps move glucose into muscle and liver tissue, where it is stored as glycogen—a reserve energy source your horse can draw on during exercise.

It’s also important to understand that not all carbohydrates are the same. Structural carbohydrates—the fiber in hay and pasture grass—are fermented in the hindgut and provide slow, steady energy.

Non-structural carbohydrates, on the other hand, are digested quickly and can cause rapid spikes in blood glucose. Feeds like corn, oats, and barley are naturally high in NSCs.

For healthy horses, NSCs play an essential role in maintaining energy and supporting performance. However, too much sugar and starch can overwhelm the digestive system and may pose problems for horses with metabolic concerns. For this reason, many horse owners are exploring low-NSC feeding programs that support equine health and performance without excess starch or sugar.

What’s Considered a Low NSC Diet & When is it the Right Choice for Your Horse

For some horses, a low-NSC diet is essential for health and long-term soundness. A low-NSC diet for horses that need or benefit from it helps manage and prevent issues linked to excess starch and sugar, promoting more consistent energy, better metabolic balance, and healthier digestion.

While not every horse needs an extremely low-NSC diet, there’s been a clear shift away from traditional, high-starch feeds in modern equine nutrition. Classic “sweet feeds,” for example, often contain 40–60% NSC, which is excessive for all horses. Today, a low-NSC feed is generally defined as containing less than 20% NSC, while those under about 13% are considered very low NSC.

Horses That Require a Low NSC Diet

For some horses, a low-NSC diet isn’t just beneficial—it’s medically essential. When combined with thoughtful forage selection and guidance from an equine nutritionist, a low-NSC feeding program becomes an essential part of maintaining health in horses with certain medical conditions.

Horses with the following conditions are susceptible to excess sugar and starch, which can worsen their symptoms or increase the risk of related health issues.

  • Equine Metabolic Syndrome (EMS) and Insulin Resistance (IR): Horses with EMS or IR have abnormal insulin responses to sugar and starch, putting them at high risk for laminitis. Strictly limiting overall NSC intake in their diet helps regulate blood glucose, prevent insulin spikes, and support overall metabolic balance.
  • Pituitary Pars Intermedia Dysfunction (PPID): Also known as Cushing’s disease, many PPID horses also develop insulin dysregulation. Feeding them like EMS horses—with low-NSC diets—can help reduce the risk of laminitis and improve overall metabolic stability.
  • Polysaccharide Storage Myopathy (PSSM Type 1): This genetic muscle disorder causes painful tying-up episodes. Low-NSC diets shift the horse’s energy source from starch to fat and fiber, which reduces muscle stiffness and supports performance.
  • Developmental Orthopedic Disease (DOD): In growing horses, managing NSC intake levels can help prevent uneven growth rates and support healthy bone development.

Horses That May Benefit from a Low NSC Diet

Some horses may not require a low-NSC diet but can still benefit from a lower-starch, lower-sugar feeding program. The types of horses that may benefit from a low NSC diet include:

  • “Hot” or Hyperactive horses: High-sugar and starch feeds can make some horses more reactive or challenging behaviorally. NSCs can trigger a rapid spike in blood glucose, providing a quick burst of energy. When that energy isn’t burned off through exercise or turnout, it can lead to excitability or nervous behavior in some horses. Lowering NSC intake may promote a calmer attitude and steady energy.
  • Overweight or easy-keeper horses: Lowering NSC intake helps stabilize glucose and insulin levels, making weight management and fat reduction safer and more effective for horses.
  • Horses prone to digestive upset: Excess starch that escapes digestion in the small intestine can ferment in the hindgut, leading to gas, acidosis, or even colic. Lower NSC reduces the risk of digestive upset.
  • Performance horses in light to moderate work: Many performance horses in light to moderate work can meet their energy needs through fat- and fiber-based diets instead of starch-heavy feeds. These energy sources offer several benefits, such as less digestive strain and steadier energy levels. 

When a Standard Feed May Still Be the Better Choice

While low-NSC diets are essential for some horses, those without metabolic sensitivities often perform best on a balanced diet that includes moderate NSC, quality fat, and digestible fiber levels. This combination provides steady energy while avoiding the drawbacks of high-sugar, high-starch feeds.

For healthy high-performance horses in regular work, ultra-low-NSC feeds that do not balance total nutrients may not provide enough glucose for proper glycogen replenishment, which is essential for muscle recovery and endurance. These horses often perform best on feeds with moderate NSC and around 10–12% fat, providing efficient energy without disrupting fiber digestion. 

How to Read Horse Feed Labels to Determine NSC Values

Interpreting horse feed labels takes a bit of work, since feed manufacturers are not required to list NSCs directly on the guaranteed analysis. Understanding what to look for helps you make informed decisions and select the proper feed for your horse’s needs.

Start by checking the feed tag for starch and sugar values—these two components make up NSC. Some labels may list “Starch (%)” and “Sugars (%)” or use the terms WSC (water-soluble carbohydrates) and ESC (ethanol-soluble carbohydrates) instead.

  • Calculate NSC: If NSC isn’t listed as a single number, add together the starch and WSC (or ESC) percentages to estimate total NSC.
  • Review ingredients: Feed ingredients are listed in descending order by weight. If grains such as corn, oats, barley, or molasses appear near the top, the feed likely has a higher NSC level. Low-NSC feeds often list fiber sources first, such as beet pulp or soy hulls.
  • Check for “maximum” guarantees: Some feed tags include a guaranteed maximum for starch or sugar. This gives you a better sense of the highest NSC value across batches.
  • Watch for “as-fed” vs. “dry matter” basis: Feed tags typically list nutrient values on an “as-fed” basis, whereas hay analyses are reported on a “dry matter” basis. To make an accurate comparison between the two, the values must be converted to the same basis.

Determining Total NSC Intake

The NSC percentage printed on a bag is just a starting point—the total daily intake determines your horse’s actual sugar and starch load.

  • Include all NSC sources: NSC comes from hay, pasture grass, concentrates, supplements, and even treats. Since forage makes up most of the diet, testing hay or pasture is the only way to determine its NSC level and the total NSCs in the horse's diet. 
  • Consider feeding rate: A feed that has a slightly higher NSC percentage but is fed in small amounts—such as a ration balancer—may actually deliver less total sugar and starch than a lower-NSC feed that’s fed in larger quantities.

Strategies for Creating a Low-NSC Feed Program with Tribute Nutrition

Designing a low-NSC feeding plan starts with understanding your horse’s individual needs. Horses with metabolic concerns, such as EMS, PPID, or PSSM, require feeds that minimize starch and sugar intake while still providing balanced nutrition.

Tribute Nutrition offers several low-NSC full-take grain concentrate products—including Kalm ‘N EZ® or Seniority™ Low NSC—formulated to provide controlled energy from fat and fiber rather than quick-burning carbohydrates.

Ration balancers like Essential K® or a soy-free textured option like Wholesome Blends® Balancer are excellent low-NSC options for easy keepers or horses on forage-only diets. They provide concentrated amino acids, vitamins, and minerals without excess calories, sugar, or starch.

A successful low-NSC feed program for horses begins with a hay analysis to determine the NSC level in your forage, since a significant amount of the horse’s sugars and starches come from hay or pasture grass. Using that information, you can confidently choose a Tribute feed tailored to your horse’s specific workload, body condition, and forage type.

Through Tribute’s free personalized feed program, you can work one-on-one with their equine nutrition team to identify the best products based on your horse’s health, workload, and forage. From there, the Tribute team helps fine-tune the overall diet to ensure balanced nutrition and peak performance.

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Article By:
Nicole Rambo, Ph.D.
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