You’ve survived a whole week without added sugars! Congratulations! Here’s some more motivation to keep you going:
The most prevalent types of added sugar Americans consume contain two monosaccharides, glucose and fructose. It’s useful to understand the physiologic response of the body to each.
When you eat a food prepared with added sugars, the physiologic response starts with the first bite of food in your mouth. Taste receptors stimulated by intense sweetness signal the reward center of the brain, which releases pleasure neurotransmitters like dopamine via the mesolimbic pathway. The more frequently you consume added sugars, the less dopamine you get in response (this is known as “tolerance” in the addiction model), meaning you need more sugar to get the same amount of pleasure. And there are a few other similarities to the addiction model…the more added sugar you eat, the more you’ll crave it and the less you’ll feel able to resist it, partly in response to serotonin depletion. (1)
Once you swallow, those added sugars will move to your stomach and then to your intestine, where they will be absorbed into the blood stream as glucose and fructose. Glucose does not need any processing and will raise your blood sugars immediately. The body then releases insulin to help normalize blood sugars. Insulin lowers blood sugars by moving the glucose into cells and glycogen stores as needed, and then moving the rest into fat cells for storage. If blood sugar levels spike (as they can be if you ate a large portion of added sugars), then insulin levels will spike too. Too much insulin often leads to low blood sugar levels within the first 2 hours after eating, which turns on the hunger cue. This means you eat lots of calories, store much of them as fat, but end up quickly ravenous and need to eat even more calories…leading to weight gain and obesity.
Another important thing you should know about insulin: it prevents us from accessing and using the energy stored in our fat cells. The more hours of the day that your insulin levels are HIGH, the less hours of the day you can burn your fat stores. So even if you restrict calories overall, if many of the calories you do get come from added sugars, you can’t access the energy in your fat stores. This leads to a slow down in metabolic rate to compensate for the decreased calories INSTEAD of the desired fat loss. Lastly, chronically high insulin levels leads to insulin resistance, which leads to even higher insulin levels in the future. So to sum up, the metabolic impacts of elevated blood glucose include:
- elevated insulin levels—> fat storage, hunger and increased calorie intake, inability to use existing fat for fuel, insulin resistance
Now what about the fructose that enters your blood stream after eating foods prepared with added sugars? Fructose must be processed in the liver. These are the metabolic impacts of the liver having to process a lot of fructose:
- decreased circulating leptin (satiety hormone) —> increased portion sizes, overeating (2)
- elevated triglycerides, lower HDL (good cholesterol) and elevated VLDL —> elevated risk of cardiovascular disease (2)
- Hepatic De Novo Lipogenesis (the liver makes new fat molecules out of the fructose) (3)
- Storage of fat in the liver itself —> Nonalcoholic Fatty Liver Disease (3)
As you can see, overconsumption of added sugars creates a cascade of negative impacts for your health and weight…but none of that is happening in your body while you’re on the challenge!
For more information on how dietary choices impact your body, call to schedule an appointment today!
Lindsay Pasdera, MS RDN