Best foods to eat the day before a blood test for optimal results

Posted By Suborna Fermi Posted on Jul 06, 2025

Keeping yourself prepared for a blood test is not just about overcoming the fear of needles and managing your craving for food before tests that demand fasting. The types of foods you eat the day before a blood test may significantly affect your test results, which may end up making you pay for the same test twice.

Diet matters before a blood test. There are foods that may abnormally elevate the levels of certain mineral levels in your blood. As a result, the test report accuracy can be hampered, which may lead to misinterpretations and even faulty treatments. There are foods you may consider having and foods you should avoid before a blood test for optimal results.

Which foods can you consume before a blood test?

• Lean proteins: Lean proteins are slow-digestive, so they are less likely to cause any sudden spike or drop in blood sugar levels. You may consider having grilled chicken or fish.
• Complex carbohydrates: Complex carbohydrates's process of releasing sugar in the bloodstream is slow and gradual, unlike simple sugars. Therefore, it helps to maintain stable blood sugar levels. You may consider choosing whole grains over refined grains.
• Healthy fats: Polyunsaturated fats and monounsaturated fats have several health benefits and they can help you keep your blood sugar levels well-stabilized. Hence, you may consider having seeds, avocados and nuts.
• Fruits and vegetables: Fruits and vegetables have always been known for having lots of health benefits. However, some of those are rich in natural sugars that you may consider having before any test that is performed to measure blood sugar levels. You may consider having raspberries, celery, leafy greens, cucumbers or cruciferous vegetables.
• Fiber-rich foods: Foods that are high in fiber not only help to regulate blood sugar levels, but also contribute to digestive health. You may consider having foods like oats, lentils and beans.

Which foods should you avoid before a blood test?

• Avoid high-sugar drinks and high-sugar foods as that may significantly affect the blood sugar levels.
• Consider limiting the intake of saturated fats and trans fats because they can temporarily elevate the levels of triglyceride.
• Processed foods are known for having high levels of unhealthy fats, sodium as well as added sugars, which may impact several types of blood test results.
• Avoid the consumption of alcohol for at least 24 hours before a blood test because alcohol intake may highly influence triglyceride levels, blood sugar levels and may also affect a liver function test.
• If you are about to get a test for stress hormones, avoid the consumption of caffeine as caffeine may increase blood pressure as well as heart rate.
• High sodium consumption may affect kidney tests, so consider avoiding highly salted foods like canned soup or fast foods.

Getting the right food the day before the blood test is compulsory, however, there are other crucial guidelines too that you need to follow. Consider having a discussion with the healthcare providers for a better understanding.