Ensure can provide nutrition when you’re struggling to eat during a bout of diarrhea, but certain Ensure products can actually make diarrhea worse. The key is choosing the right variant and drinking it the right way. High-sugar, high-fat formulas like Ensure Plus are known to worsen loose stools, while lower-fat options like Ensure Original or Ensure Clear are generally easier on the gut.
Why Some Ensure Products Worsen Diarrhea
Liquid nutritional supplements are concentrated sources of sugar, fat, and protein dissolved in a relatively small volume of fluid. When a high-solute liquid reaches your small intestine, your gut responds by pulling extra water into the intestinal space to dilute it. This influx of fluid is exactly what produces watery, loose stools. The more sugar and fat packed into a formula, the stronger this effect.
Memorial Sloan Kettering Cancer Center specifically advises avoiding Ensure Plus and Boost Plus during diarrhea because they are high in both sugar and fat. These calorie-dense products are designed for people who need to gain weight, not for someone with an already irritated digestive system.
Which Ensure Products Are Safer
Not all Ensure formulas carry the same risk. Ensure Original and Ensure High Protein are lower in fat and sugar than the “Plus” versions, making them easier to digest when your gut is sensitive. If even those cause problems, Ensure Clear is the gentlest option. It’s a clear liquid supplement with less fat, and MSK recommends diluting it: mix half a cup of Ensure Clear with half a cup of water to reduce the concentration further.
That dilution step matters. By lowering the concentration of dissolved nutrients hitting your small intestine at once, you reduce the osmotic pull that draws water into your gut. Think of it as giving your digestive system less work to do per sip.
How to Drink It Without Making Things Worse
Even with a gentler formula, how you drink it is just as important as which one you choose. Gulping down a full bottle floods your small intestine with a concentrated load all at once. Instead, drink only one-third to one-half cup at a time. That’s roughly 80 to 120 milliliters, or a few small sips spread out rather than a full serving in one sitting.
Sipping slowly throughout the day lets your gut absorb nutrients gradually. You’ll still get the calories and protein you need, but without overwhelming a digestive tract that’s already struggling. Room temperature or slightly cool liquid tends to be better tolerated than ice-cold drinks, which can stimulate gut contractions.
The Role of Fiber in Ensure
Some Ensure products contain added fiber, which plays a complicated role during diarrhea. Soluble fiber can actually help firm up loose stools by absorbing water in the colon and slowing down how fast food moves through your digestive system. It also gets fermented by gut bacteria into compounds called short-chain fatty acids, which help your colon reabsorb water and electrolytes.
Insoluble fiber works differently. It adds bulk to stool and can trigger what’s called the “ileal brake,” a natural mechanism that slows gastric emptying and increases transit time through the small intestine. In theory, this means food spends more time being absorbed and less time rushing through. A meta-analysis of randomized controlled trials published in Frontiers in Nutrition found that fiber-supplemented enteral formulas showed benefits for preventing diarrhea in hospitalized patients, with soluble fibers like soy polysaccharide and psyllium performing well.
That said, if your diarrhea is already severe, adding fiber-rich formulas without medical guidance can sometimes increase bloating and gas. For mild to moderate diarrhea, a fiber-containing Ensure variant may help stabilize things over a few days.
What Ensure Won’t Do
Ensure is a nutritional supplement, not a diarrhea treatment. It won’t address the underlying cause of your diarrhea, whether that’s a stomach virus, food intolerance, medication side effect, or something else. Its value is in keeping your nutrition and calorie intake from collapsing while your gut recovers. During diarrhea, your body loses fluids and electrolytes rapidly, and Ensure alone doesn’t replace electrolytes the way oral rehydration solutions do.
If you’re relying on Ensure because you can’t tolerate solid food, pair it with an electrolyte drink or oral rehydration solution to cover what Ensure doesn’t. Water alone isn’t enough when you’re losing significant fluid through diarrhea, because it doesn’t replace the sodium and potassium your body is shedding.
Quick Reference by Product
- Ensure Plus, Boost Plus: Avoid during active diarrhea. Too high in sugar and fat.
- Ensure Original, Ensure High Protein: Lower in fat and sugar. Generally tolerable if sipped slowly in small amounts.
- Ensure Clear: Gentlest option. Dilute 50/50 with water for best results.