Blood Sugar Levels and Diabetes

Blood sugar, or blood sugar, needs to be in a normal range for you to be healthy. At least some blood sugar is necessary for your muscle, liver, and some other cells to use as fuel so they can function. 

Abnormal – too much or too little sugar, though, is dangerous. Too little blood sugar, or hypoglycemia, can make you weak or even lead to loss of consciousness. [1] On the other hand, hyperglycemia, or too much blood sugar in your blood, can also become an emergency or lead to diabetes complications. [2] A blood sugar chart can help you remember which levels you should have, especially if you’re not diabetic yet and want to keep it at bay.

Normal and Abnormal Blood Sugar Levels and What They Mean

The ranges of normal levels of blood sugar depend on factors such as what time of day it is and when you last ate. Safe levels of blood sugar are high enough to supply your organs with the sugar they need, but low enough to prevent symptoms of abnormal blood sugar. Dangerous levels of blood sugar are outside of this range.

The target levels can also vary if you have diabetes. For example, if you are diabetic and are monitoring your blood sugar, you might get a reading of 65 mg/dl. That is considered to be mild hypoglycemia, and you would be wise to eat 15 grams of fast-acting carbohydrates and retest your blood sugar in 15 minutes. 

If you were not diabetic, you probably would not know that your sugar was low because you would not test and because you would not have symptoms, and you would not act. That is fine because your body is capable, under normal circumstances, of raising your blood sugar to healthy, normal levels when needed, even if you have not eaten. That’s the primary difference between someone who has diabetes and someone who doesn’t.

Blood Sugar Levels in the Morning

The best time to check blood sugar levels in the morning is right when you wake up and before you eat anything. This gives you a glimpse of what may be happening overnight, and it gives you a baseline for the day.

These are goal levels, according to Joslin. [3]

  • Under 70 mg/dl if you do not have diabetes.

  • 70 to 130 mg/dl if you have diabetes.

The dawn effect can often lead to a high morning measurement in diabetes. This is your body’s tendency to get ready for the day by raising blood sugar by increasing levels of counter-regulatory hormones – the ones that counteract insulin. With diabetes, you do not have the capacity to counterbalance this rise in blood sugar, so levels can be dangerously high. [4]

Ways to lower your morning blood sugar value include:

Normal Blood Sugar Levels after Eating

Many foods have types of carbohydrates called starches and sugars. When you eat foods with these types of carbohydrates, your body breaks them down into sugar, which is a type of simple sugar, and releases the sugar into your bloodstream. Aside from sugar produced by your liver, food is the main source of blood sugar.

After eating, your blood sugar levels rise. They rise more when you eat more carbohydrates, when you do not eat fiber, fat, or protein with your carbs, and when you eat certain types of carbohydrates, such as refined sugars and starches.

You might want to measure your blood sugar before meals to get a baseline, and then two hours after your meal. Your doctor might also suggest measuring blood sugar before bed to be sure you have been eating well throughout the day and can go to sleep with peace of mind. These are target normal values. [5]

When Measured Goals for Healthy Adults Goals with Diabetes
Before lunch, dinner, or a snack
Less than 110 mg/dl
70-130 mg/dl
2 hours after you eat
Less than 140 mg/dl
Less than 180 mg/dl
Before bedtime
Less than 120 mg/dl
90-150 mg/dl

Hemoglobin Chart

Hemoglobin is the oxygen-carrying protein in your red blood cells, but it is highly relevant to blood sugar levels. Sugar in your blood attaches to hemoglobin, creating what is called glycated hemoglobin, or A1C. High blood sugar levels lead to more hemoglobin being glycated.

Measuring your A1C is an alternative to measuring fasting blood sugar. Measuring blood sugar directly with a finger prick or a blood draw at your doctor’s office lets you know your blood sugar at that moment, while the A1C value you get provides an estimate of your average blood sugar levels over the past 3 months.

Glycated Hemoglobin (A1C) Value Estimated Average Glucose (EAG)
5.6% (Highest “normal” value)
114 mg/dl
5.7% (Prediabetes)
117 mg/dl
126 mg/dl
6.4% (Diabetes)
137 mg/dl
7% (Goal in diabetes)
154 mg/dl
183 mg/dl
212 mg/dl
240 mg/dl

Printable Blood Sugar Chart

A blood sugar chart showing goal values can help you quickly gauge how you are doing with your monitoring. This chart shows what to aim for throughout the day if you have diabetes or not. [9]

Time and Situation Goal for Non-Diabetics Goal for Diabetics
First thing in the morning (fasting before breakfast)
< 100 mg/dl
70 – 130 mg/dl
Before lunch, dinner, and snacks
< 110 mg/dl
70 - 130 mg/dl
Two hours after starting to eat a meal or snack
< 140 mg/dl
< 180 mg/dl
Before going to bed
< 120 mg/dl
90- 150 mg/dl

You can also click here for a printable blood sugar chart showing target values at different times of the day for diabetics and non-diabetics.

If you’re worried about your blood sugar levels, take Lark’s 1 minute quiz and see if you are at risk of prediabetes: