Where Does Energy Come From?
It’s no secret that our bodies use food to energize us and keep our systems running. Carbohydrates are our bodies’ main source, or you can “burn fat for fuel”. But what does that all really mean? Understanding these systems can help you make better decisions for your health.
Energy From Carbs
Let’s start with the big one – carbohydrate metabolism! Basically, how your body processes carbohydrates from food and turns it into fuel.
Carbohydrate-rich foods include grains, sugar, starchy vegetables, fruits, and many processed foods. When you eat something with carbohydrates, your body begins a cascade of effects to make the most of it. Soon after consumption, your body breaks larger carbohydrate molecules down into simple sugars, which are absorbed into the bloodstream. Your blood sugar rises, which triggers the pancreas to release a hormone called insulin. Insulin is needed in the process to move sugar from the blood into the cells, where the sugar can be used as a source of energy.
Types Of Carbs
There are different types of carbohydrates. Most generally, there are “simple” and “complex” carbs. Simple carbs or “simple sugars” might be sugar itself, in the form of sugar-sweetened beverages, candies, or processed foods. Complex carbs might be whole grains or vegetables. The more simple the carb, the faster it goes through the metabolism process, making you feel hungry faster. In other words, eating complex carbohydrates helps you stay energized over a longer period of time.
This process is also the reason for blood sugar spikes. Simple or quick carbs cause your blood sugar level to rise more quickly (increased blood glucose). We rate how fast or slow carbohydrates are turned into blood glucose are measured on the Glycemic Index. Issues or abnormalities with the stability of your blood glucose level is a sign of diabetes, or pre-diabetes.
Energy From Fat
We can also use fat for energy. High-fat foods include oils, nuts, seeds, avocados, some meats, and some dairy products. This is a topic that has been talked about more and more as the ketogenic and other low-carb diets have become popular. A keto diet is different than other low-carb diets, though. A keto plan centers on fat, which supplies as much as 90% of daily calories. When you do this, your body runs on ketones for fuel (which we’ll get into below). It’s not an easy thing to do, and how little carbohydrate one needs to eat to get into ketosis varies from person to person.
The Keto Diet
A little background, “The keto diet is primarily used to help reduce the frequency of epileptic seizures in children. While it also has been tried for weight loss, only short-term results have been studied, and the results have been mixed. We don’t know if it works in the long term, nor whether it’s safe,” states registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women’s Hospital.
Back to ketosis: instead of utilizing sugar (glucose) that comes from carbohydrates, the keto diet relies on ketone bodies (or ketones), a type of fuel that the liver produces from fat. When you’re eating carbohydrates regularly, your body stores any excess for later use. When you stop eating carbs, you deplete these stores. Once they run out, your body begins the process to start using fat for fuel instead.
Additionally, without other factors, your liver does produces a small amount of ketones on its own. As your blood glucose decreases, insulin levels decrease and this tells your liver to produce more ketones in order to provide enough energy to the brain. This continues until you’re in a state of ketosis, where your body is using ketones as fuel.
Truly achieving ketosis and getting the liver to make ketone bodies is tricky because of how little carbs you need to consume. Typically, it takes fewer than 20 to 50 grams of carbs per day (to compare, a medium-sized apple contains around 25 grams of carbohydrates alone). Additionally, it typically takes a few days to reach a state of ketosis, and it can be thrown off by consuming too much protein.
Cronometer offers several settings to cater to users on the keto diet such as the Keto Calculator, the Ketogenic Nutrition Score and integrating with two different ketone breath monitors, KetoMojo and BioSense. Working with a nutrition professional might also improve success with this diet.
Choose What Works Best for You!
It is pretty amazing that our bodies can use multiple fuel sources. Evolutionarily, it allowed us to eat a varied diet, have periods of fasting, and still maintain an active state. We’re learning more about the keto diet, energy, and carbs all the time. What’s becoming more apparent in the field of nutrition is that no one diet works for everyone.
Tracking your nutrition in Cronometer is an excellent start to a healthier, more energetic life! If you’re thinking about trying a new way of eating but aren’t sure how to get started or if it will work for you, we suggest working with your doctor or a registered dietitian.