Confused about blood sugar? Here’s a quick and basic overview of what it is, what kinds of diet and lifestyle factors can affect it, and what that means from the perspective of a Paleo diet and lifestyle framework.
What Is Blood Sugar?
The "sugar” in “blood sugar” isn’t the same thing as table sugar. Biologically, “sugars” are simple carbohydrates, the building blocks of all the carbohydrates in everything you eat (including table sugar, but also including other foods that contain carbohydrates, like potatoes).
One type of simple carbohydrate or “sugar” is glucose, which is the “sugar” measured when somebody measures your “blood sugar.” A more accurate name for it is “blood glucose,” which is what you’ll see in most studies.
So having high blood sugar doesn’t mean that you ate a lot of table sugar and the sugar is now in your bloodstream; it means you ate a lot of carbohydrates (from any source) and the sugar (glucose) is now in your bloodstream. Any digestible carbohydrate can raise blood sugar, although some raise it higher and faster than others.
Problems with Blood Sugar Regulation
In healthy people, blood sugar is automatically regulated. You eat some carbs and your blood sugar rises, but insulin appears to the rescue and lowers blood sugar levels by storing the glucose for you to use later between meals (that’s an incredibly simplified explanation, and the reality is very complicated, but if you want more on insulin, you can read about it here).
That’s how it works in healthy people. But problems with blood sugar regulation are incredibly widespread. In fact, some of them are so common we’ve almost stopped seeing them as problems – like the mood and energy rollercoaster that leaves you trying to drag yourself out of a midmorning slump with a bagel or some crackers, and a midafternoon crash with a candy bar.
A related problem is chronically high blood sugar (hyperglycemia). The extreme end of the hyperglycemia scale is Type 2 Diabetes, but just because you haven’t been diagnosed with diabetes doesn’t mean your blood sugar is healthy!
Massive swings between high and low blood sugar have health dangers on top of being pretty unpleasant, and chronically high blood sugar is also unhealthy – for one thing, because it can develop into Type 2 Diabetes. Obesity is very tied up with poor blood sugar regulation, and other metabolic problems. But not all obese people have blood sugar regulation problems, and not all people with high blood sugar are obese.
Diet and Blood Sugar: The Whirlwind Tour
Diet has a huge effect on blood sugar control, but the question of which specific diet works the best is really complicated and depends a lot on the particular person. Blood sugar control is a complicated hormonal issue. Here’s the lightning-fast overview, with links to more reading if you’re interested in the evidence behind particular claims.
Carbs and Blood Sugar
The more concentrated glucose a carbohydrate source contains, the faster and higher it tends to raise blood sugar. In practice, this means that refined carbs (white bread, pretzels…) raise blood sugar higher and faster than foods where the digestible carbohydrates are less concentrated and more of the bulk is made up of fiber (which is indigestible to you, so it doesn’t raise blood sugar). Fructose doesn’t raise blood sugar as fast, but that doesn’t necessarily make it better: fructose has problems of its own.
For most people, eating a lot of highly refined carbohydrates on a regular basis is too much for their body to handle and tends to cause hormonal and metabolic problems down the line (sometimes culminating in metabolic syndrome or Type 2 Diabetes). Low-carb diets can be a very effective therapy for people with pre-existing blood sugar or insulin problems, especially problems that were caused by an overload of refined carbohydrates in the first place. (Although as always, if you have a serious health problem like diabetes, talk to your doctor before you try to treat yourself with food!)
On the other hand, low-carb diets aren’t necessary or even healthy for everyone. Most people can handle a moderate amount of glucose without developing any blood sugar problems. There are hormonal and other benefits to eating carbs, and if you do fine with them, there’s no need to make your diet unnecessarily restrictive.
Humans are highly adaptable omnivores. The modern junk-food diet is biologically extreme: just because we get sick on that doesn’t mean we can’t handle any carbs at all. Carbohydrates from fiber-rich, nutrient-dense whole foods like potatoes and sweet potatoes avoid a lot of the problems with refined, processed carbohydrates, and it doesn't make sense to tar them all with the same brush.
Other Nutrients and Blood Sugar
Carbs aren’t the only factor affecting your blood sugar. Eating a carbohydrate source with protein and fat will change its effect on blood sugar levels. If you’ve heard of the glycemic index (GI), this is why GI alone (without considering other factors) isn’t a great measurement in the real world: it only measures the effect a food has on your blood sugar if eaten completely alone without anything else.
There’s also some evidence that some other nutrients – for example, phytonutrients in certain spices – can affect the blood sugar response to a meal. Gut health also affects blood sugar regulation, and gut health is affected by just about everything you eat. So your whole diet is important when it comes to blood sugar: it’s not just how many and what kind of carbs you eat.
So What Should I Eat?
Hold that thought for just a second, because the answer also depends on lifestyle factors.
Lifestyle and Blood Sugar Control: The Usual Suspects
Diet is important for good blood sugar control, and you can get a long way on diet alone. But it’s not everything, and diet and lifestyle changes have a mutually reinforcing effect, where making healthy changes in one area makes it easier to do the same in the other. So here’s the quick overview of lifestyle factors to pay attention to for blood sugar control:
- Sleep: sleep deprivation or sleep disturbance (e.g. sleep apnea) can make blood sugar regulation much harder.
- Stress: Chronic stress (psychological or physical) is a huge problem for blood sugar regulation; you can read more about it here.
- Exercise: exercise is great for blood sugar control and metabolic health. You can use this handy infographic to compare different types of exercise for blood sugar regulation, but here’s a spoiler: they’re all helpful, even walking.
Paleo and Blood Sugar
Paleo is designed to be a good diet for blood sugar regulation right out of the box: that’s one major reason why the Paleo template looks the way it does.
- The typical interpretation of Paleo – plenty of animal protein and healthy fats, lots of fiber-rich vegetables, and carbs to your individual tolerance – was designed to help regulate blood sugar, improve metabolic health, and get hyperglycemia under control.
- On top of the dietary aspects, Paleo also stresses lifestyle factors like sleep, stress management, and exercise: these things are just as important for your overall health as your diet.
Within that template, there’s a huge range of possibilities for individual people to figure out what carb intake is best for controlling their blood sugar. For some people, a basic Paleo template with carbs when they feel like it works just fine with no adjustment necessary.
Another popular approach is to start by eating starchy vegetables (potatoes and sweet potatoes) after exercising, and then tweak up or down from there. “It depends” is always an unsatisfying answer, but in this case, it’s really true: eating for blood sugar control will probably look very different for a lean 21-year-old athlete than it will for an overweight 55-year-old couch potato.
Regardless of how many grams of carbohydrate you end up eating, though, Paleo is a pretty great framework for helping you figure it out – and for helping address all the other factors that go into blood sugar control besides just the carbs.