Diabetes, Carbohydrate, the Glycemic Index, and the Ketogenic Diet

The lower your carbohydrate intake, the lower your blood glucose will be, right?!?

You need 400-600 calories from glucose every day to fuel the brain, spinal column, and nervous system. An adult should never eat less than 130 grams of carbohydrate a day (175 grams for pregnant women). This amount of carbohydrate is the bare minimum that your body needs as fuel and should not be misinterpreted as a “goal.” Carbohydrate is what stimulates the beta cells of your pancreas to release insulin. For people with type 2 diabetes who are not secreting enough insulin, low-carbohydrate diets will do more harm than good. Very low carbohydrate diets (those containing less than 20 grams of carbohydrate a day) can lead to ketosis, electrolyte loss, and dehydration. If followed for a while, they can exacerbate kidney disease and gout and may cause bone loss. People who have diabetes and are also dealing with kidney, liver, or heart disease should never follow a very low carbohydrate diet. LDL (the bad cholesterol) increases, sometimes drastically, on a low-carbohydrate diet. LDL cholesterol is the #1 marker of heart disease.

So there’s no reason for me to watch my carbohydrate intake?

You still need to keep a close eye on your carbohydrate consumption. When people reduce their carbohydrate intake from 55-60% to 40% of total calories, they experience a significant reduction of visceral fat and a marked improvement in insulin sensitivity. Visceral fat is significant because this is the fat that surrounds your organs and can build up in the arteries. Excess visceral fat increases your risk of heart attacks and heart disease, stroke, breast cancer, colorectal cancer, Alzheimer’s disease, and liver disease (among others). Reducing carbohydrate intake to 40% of calories while increasing protein intake from the standard 15% to 20-30% will also reduce blood triglycerides and increase HDL cholesterol (the “good” cholesterol). 

Everyone is telling me to eat more protein. Is it really necessary?

As long as you’re getting at least 20% of your total calories from protein, you’re probably OK. Twenty percent of calories equates to 75 grams on a 1500 calorie diet and 100 grams on a 2000 calorie diet.

It is common for people to hear that they should eat protein if their blood sugar drops too low. Still, there is no proof that adding protein to meals or snacks will help prevent hypoglycemia or assist in the treatment of hypoglycemia. Eating protein will increase the insulin response, so that blood glucose decreases. Therefore, protein-rich foods should never be used in the treatment of hypoglycemia. Straight carbohydrate (15 grams and then wait 15 minutes and if still low, eat another 15 grams) is the way to go if your blood sugar drops too low.

What about the ketogenic diet for diabetes?

The fat that is stored in muscle is called intramyocellular fat. Your intramyocellular fat levels will remain elevated on the ketogenic diet, which means you will still be insulin resistant while on the ketogenic diet. Additionally, your insulin levels drop when you eat a high-fat meal – not exactly great news for someone with diabetes. In fact, in one study, participants needed an average of 42% more insulin after a high-fat meal compared to a low-fat meal. Despite receiving additional insulin, their blood glucose remained elevated for 5-10 hours after the meal. High-fat meals also delay gastric emptying, which leads to unpredictable food absorption. If you’re on insulin, you might need to adjust your dose to compensate for a high-fat meal. Otherwise, you’ll likely experience hypoglycemia right after eating and rebound hyperglycemia a few hours later.

Additionally, both saturated fat and trans-fat exacerbate insulin resistance by interrupting the signals sent between the insulin and the cells that pick up the insulin. They also increase LDL cholesterol and decrease HDL cholesterol, precisely the opposite of what you should be striving towards. As soon as you eat something “off-plan,” your blood sugar levels will shoot up, and you’ll rapidly regain any weight that you’ve lost. The formation of ketone bodies causes water loss, nausea, and appetite loss to lose weight in the short-term. Ultimately, though, the ketogenic diet is destined to fail.

What about the glycemic index (GI)?

There is no standard definition of a low GI diet, and people who attempt to follow a low GI plan for any length of time are likely to miss out on nutritious food and the vitamins and minerals in these foods. For example, watermelon has a higher GI than ice cream. Does this mean that you should avoid watermelon and indulge in a sundae? M & M candies have a lower GI than pasta. Should you eat a bag of M & M’s while the rest of the family is eating pasta? The GI has nothing to do with the nutritional quality of food; for example, you wouldn’t eat pineapple or sweet potatoes on a low GI diet, but these are very nutritious foods. As for those carrots that are supposedly so damn high in sugar? If one more person tells me that they avoid carrots because of this, I do fear that my head will explode. A pound and a half of carrots have the same amount of carbohydrate and, therefore, a similar GI as pasta does. How likely are you to eat a cup of pasta at one sitting? Oh, very likely. How probably are you to eat a pound and a half of carrots in one sitting? Not at all. If you want to try to incorporate the GI into your diet plan, use it to make food choices within the same category, such as sourdough bread instead of white bread or al dente pasta over thoroughly cooked pasta.