Does My Horse Need a Low-Carb Feed?

Horse owners often hear the term “low-carb feed” and wonder if it’s right for their horse. Unlike in human diets, “low carb” in equine nutrition doesn’t mean cutting out all carbohydrates. Horses are grazing animals that rely heavily on fiber — a carbohydrate — for energy and digestive health. What it really refers to is reducing non-structural carbohydrates (NSC), the sugars and starches that can cause issues in certain horses.

This article breaks down what “low-carb” means in practical terms, when it matters most, and how to make the best feeding choices for your horse.

Carbohydrates in the Equine Diet

Carbohydrates provide the bulk of a horse’s daily energy. They come in two main categories:

• Structural carbohydrates: Found in hay, pasture, and other forages. These fibers are slowly fermented in the hindgut, providing steady, safe energy.
• Non-structural carbohydrates (NSC): This includes sugars and starches from grains, lush grass, and some hays. NSC is digested quickly in the small intestine, often causing sharp spikes in blood glucose and insulin.

Equine nutritionists generally use “low-carb” and “low-NSC” interchangeably. A diet that is lower in sugar and starch — while still rich in fiber — can make a significant difference for horses with certain health conditions.

When Low-NSC Feeding Matters

Not all horses require a low-NSC diet, but research shows it is especially important for horses with specific health concerns:

• Equine Metabolic Syndrome (EMS): Horses with EMS are insulin resistant and highly sensitive to sugar and starch intake. Managing NSC helps prevent dangerous metabolic spikes (Johnson et al., Equine Veterinary Education).
• PPID (Cushing’s disease): Many horses with PPID struggle with insulin regulation. Dietary management with reduced NSC is often recommended (Durham, Equine Veterinary Education).
• Polysaccharide Storage Myopathy (PSSM) and tying-up disorders: Horses with these muscle conditions benefit from diets that limit starch and sugar while relying more on fat and fiber for energy (Veterinary Medicine, UCDavis).
• Gastric ulcers or excitable behavior: Diets high in starch are sometimes linked to digestive upset and “hot” behavior, making low-NSC alternatives a good choice.

How to Evaluate Your Horse’s Diet

The first step is understanding how much NSC your horse is consuming across their entire diet.

• Forage testing: Because hay and pasture make up most of the diet, their NSC levels matter most. Forage testing, available through labs and extension services, provides clarity; however, it is not practical in the Southern US, where hay storage is limited to what can be consumed within a short period due to heat and humidity degrading the quality and nutritional value. The National Research Council’s Nutrient Requirements of Horses (2007) highlights the wide variation in hay NSC levels, even within the same cutting.
• Soaking hay: Research published in the Journal of Equine Veterinary Science shows that soaking hay in water for 30–60 minutes can reduce soluble sugar content, making it safer for metabolic horses.
• Feed labels: When contacted, many commercial feed companies will provide guaranteed maximums for starch and sugar. These levels are usually not stated on bags or tags due to the inconsistent and non-standardized testing across the US. A combined NSC of 20% or less is often considered low, though severely insulin-resistant horses may require even lower thresholds.
• Total ration analysis: Always look at the whole picture. A horse eating a low-NSC concentrate may still consume excessive sugar if their hay or pasture tests high.

What to Look for in a Low-NSC Diet

When building a safe ration for your horse:

• Aim for forage-first feeding. Grass hay with lower sugar content is often preferred for metabolic horses.
• Choose concentrates that provide transparent NSC values. Look for formulations built on fiber sources such as beet pulp, soybean hulls, and alfalfa meal.
• Ensure the diet remains balanced. Low NSC doesn’t mean low nutrition — your horse still needs adequate protein, vitamins, and minerals.
• Transition gradually. As recommended by the NRC, dietary changes should always be made over 7–10 days to protect digestive health.

Myths and Misconceptions

• “Low-carb” means no carbs. Not true. Horses require carbohydrates, particularly fiber, to maintain gut health and provide energy.
• Forage is always safe. Spring pasture or certain hays can contain high levels of NSC and must be managed carefully.
• All low-NSC feeds are the same. Quality, balance, and consistency vary. Reading labels and testing forage remain essential.

Putting It All Together

Feeding horses isn’t about removing carbohydrates — it’s about choosing the right ones in the right amounts. Low-NSC diets are supported by extensive veterinary research as a safe and effective strategy for managing conditions like EMS and PPID, while also helping sensitive horses thrive.

By testing forage, reviewing feed labels, and consulting with your veterinarian or equine nutritionist, you can build a ration that keeps your horse healthy, comfortable, and performing at their best.

The bottom line: a low-NSC diet isn’t a trend — it’s a proven approach to supporting equine health when sugar and starch become part of the problem. With informed choices, you can help your horse live a healthier, more balanced life.

Frequently Asked Questions