Feeling Dizzy and Tired on a Diet

Don't let fatigue and dizzy spells during weight loss derail your goals of getting lean and healthy. If you are feeling dizzy and tired on a diet, there are several potential causes — low blood sugar, nutritional deficiency and dehydration — which you can learn to avoid.

Learning how to spot and sidestep these causes of dieting lightheadedness can help you feel more energetic and steady while losing weight. Also, be sure to consult a medical professional to rule out underlying conditions such as vertigo, Meniere's disease and other disorders that can cause dizziness.

You might feel dizzy and tired on a diet due to a drop in blood sugar. The body's main energy source, glucose comes from the food you eat and drink and helps fuel your basic bodily functions, such as repairing cells, circulating blood and regulating temperature.

When you decrease the amount of calories you consume while on a diet, you decrease your body's fuel supply. Without enough glucose, your organs, including your brain, can't function properly. This could cause lightheadedness and lethargy.

Read more: Symptoms You May Experience During a Cleanse

To avoid low blood sugar and the dieting dizzy spells it causes, you can up your calorie intake, instead of drastically cutting calories while on a diet. According to Harvard Men's Health Watch, decreasing your calorie intake by just 10 to 15 percent can lead to weight loss and health benefits.

This means if you regularly consume 2,000 calories daily, eat 200 to 300 fewer calories per day. For a quick solution to dizziness caused by low blood sugar, eat 15 grams of carbohydrates such as small piece of fruit or 1/2 cup of juice to replenish glucose levels.

Besides supplying your body with energy in the form of glucose, food also provides nutrients, such as vitamins and minerals, which your body needs to carry out its basic functions. Because the body does not store most vitamins, deficiency can happen quickly — within a few weeks, according to the Merck Manuals. Deficiency in even one vitamin can cause malnutrition, which might be the reason for you feeling dizzy and tired on a diet.

Read more: 3 Common Vitamin Deficiencies That Cause Dizziness

Consult a medical professional before starting your diet to help you structure an eating plan that will supply you with the right amount of calories, vitamins and minerals for your body and activity level. If you've already begun a diet and suspect you might have a vitamin or mineral deficiency, your doctor can order tests such as a lipid panel or a complete blood count panel to check if you're deficient.

Dehydration could also cause lethargy and dizzy spells during weight loss, according to the Mayo Clinic. Besides feeling tired and lightheaded, if you feel woozy, have sunken eyes, headaches, dark-colored urine or an irregular heartbeat, you might be dehydrated. Make sure to drink water whenever you feel thirsty or have dark-colored urine to ward off these symptoms.

You can tell you are hydrated when your urine is light colored, you sweat continuously when exercising and when your skin instantly returns to its natural state after you pinch it. There is no international consensus on how much water a person should drink daily, as it depends on your size, activity level, health and where you live. For extra help, consult a medical professional to help you determine how much water you should be drinking each day.