Feeling Shaky After Eating? Here's Why

You've eaten, but now you're trembling. And you feel fatigued. And your head is pounding. What exactly is going on? According to the Mayo Clinic, you may have a low blood sugar condition called reactive hypoglycemia.

Also known as postprandial hypoglycemia, this condition differs from the type of low blood sugar that so often affects people with diabetes.

​Read more:​ 4 Diet Tips for Dealing With Hypoglycemia Without Diabetes

"Blood sugar is our body's fuel," explains St. Louis-based dietitian Connie Diekman, RD, MEd, a food and nutritionist consultant, former president of the Academy of Nutrition and Dietetics and former director of university nutrition at Washington University in St. Louis. "So when it drops lower than the level needed to keep all parts of the body functioning, we will often feel that impact through headaches, jitters, lightheadedness or fatigue."

Hypoglycemia is a common concern among people with diabetes, notes the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). It occurs when your blood glucose (or blood sugar) levels dip too low, typically 70 milligrams per deciliter or below.

According to the NIDDK, if you have diabetes-related hypoglycemia, underlying causes can include diabetes treatments themselves, such as insulin or diabetes pills (including sulfonylureas or meglitinides). But, the institute warns, if you have diabetes, hypoglycemia can also be triggered if you fail to eat enough carbs, skip or delay meals, exercise too much or drink alcohol, causing your blood sugar levels to go out of whack.

Mild to moderate symptoms of hypoglycemia typically happen quickly and with little warning, says NIDDK, possibly making you feel sweaty, jittery, headachy, irritable, fatigued, confused, dizzy, lightheaded or hungry. You may also experience an increased heart rate and blurred vision or have trouble concentrating.

Severe episodes, which are more common if you have type 1 diabetes, can cause such serious symptoms as seizures or loss of consciousness and should be treated immediately, according to NIDDK.

Many of the moderate symptoms associated with hypoglycemia overlap with those that occur if you have the reactive version — which, according to an explanatory article published in the ​Journal of Clinical Endocrinology & Metabolism​ (​JCEM​) in October 2013, affects people who do not have diabetes. But in other ways, the two conditions are very different.

For instance, unlike with hypoglycemia, reactive hypoglycemia attacks typically occur within a few hours after you eat a meal. Another difference: While the driving factors behind hypoglycemia are well known, ​JCEM​ notes that the jury is still out on the exact causes of the reactive version. However, having high insulin levels — and a resulting drop in blood sugar levels — is thought to be a factor.

The Mayo Clinic, for its part, notes that the condition may have something to do with the type of foods you consume or the timing of the digestive process. Drinking alcohol may also be a trigger, or you could have an inherited metabolic disorder or a tumor. If you have had stomach surgery, that could also be an underlying cause, the Hormone Health Network (HHN) points out, as it can cause food to pass into your small intestine too quickly.

The good news is that people with reactive hypoglycemia usually don't require medical treatment, according to the Mayo Clinic. When an attack happens, says HHN, you should immediately consume 15 grams of carbohydrates (juice, candy or glucose tablets) to help alleviate symptoms. That said, it's always wise to talk with your doctor about what you're experiencing, to make sure you're responding appropriately.

In addition, the Mayo Clinic stresses that people who experience reactive hypoglycemia should consider adopting a preventive diet, such as eating less meat and more whole grains, fruits and vegetables. NIDDK suggests eating smaller but more frequent meals (every three hours, for instance) and favoring foods high in fiber and low in sugar to help lessen your symptoms.

All that advice is seconded by Dallas-based dietitian/nutritionist Lona Sandon, PhD, RDN, who's also an associate professor of clinical nutrition at the University of Texas Southwestern Medical Center, Dallas. In fact, she says, being mindful of one's diet may actually help stave off the problem altogether.

"The best way to avoid this is to eat balanced meals with some protein, complex carbohydrates — such as whole grains and starchy vegetables like potatoes — and healthy fats," Sandon says. "And avoid meals and drinks high in added sugars."

​Read more:​ The Best Diet for Reactive Hypoglycemia