When we were cavemen we searched for fruit as a way to put on fat and survive during harsh conditions. Our brains are in fact wired to react to the sweet taste and stimulate our memory to remember where we found this sweet treasure so we could return for more. Over millennia our genes even altered themselves in order for us to be better suited for fat storage and thus survival. Well, the times have changed but our genes have not. There is no more famine in America and food abounds, yet our bodies are still built to store fat easily. What was once a life giving biology, eating fructose to store fat, is now chocking the life out of many of us.
All animals that hibernate seek out fruit as a way of stimulating fat storage in order to endure the hibernation. Migrating birds first seek fruit and bulk up so they have enough energy to fly hundreds of miles. But unlike humans, animals don’t stay fat. Why? Humans have genetic switches that turn on and off based on the foods we eat. Unlike animals we don’t stop eating when we are full and we don't avoid harmful foods. We will plow through a box of cookies or chips and keep right on eating. WHY?
Fructose is a simple sugar different from glucose. Fructose is found primarily in 3 places: fruit, honey, and high fructose corn syrup. 70% of all packaged foods contain high fructose corn syrup (HFCS) and most people eat primarily processed food meaning that we get a lot of fructose. We are also conditioned with the lie that “fruit is healthy”. The truth is that a little fruit, eaten occasionally, is healthy. But many of us eat 2-3 servings of high glycemic fruit each day and with each and every serving we are sending strong signals to our cells to STORE FAT. A hibernating bear might also store fat but then he hibernates he STOPS eating and burns the fat off. We just keep on eating.
Fructose is the only known food that will lower the energy within a cell. When we overeat HFCS or fruit and honey this drives lethargy as the cells lose energy. We are less likely to be motivated to exercise. More importantly this wave of fructose turns off a very critical switch called AMP-Kinase. AMP-Kinase drives the cell to use fat as fuel but when exposed to fructose this switch is turned off and the cell is instructed to SAVE FAT and store it as much as possible. If we measured labs we would see triglyceride levels go up, blood sugar rise, and levels of uric acid increase. Uric acid at high levels will cause gout. But even at temporary lower levels, uric acid alters our kidneys and drives blood pressure up. In a study of healthy people, eating fructose increased their blood pressure for a few hours post ingestion.
Fructose has an amazing ability to drive our appetite. Eating fructose stimulates us to want to eat more. In mouse studies when 2 groups of mice we given similar diets but one group received fructose in their water, they ate more food and gained more weight than the fructose-free mice. In a different study 2 groups of mice were fed the exact same number of calories but one group received some of those calories as fructose. Only the fructose-fed rats developed high levels of uric acid, triglycerides and rising insulin levels suggesting greater risk for diabetes.
Metabolic Syndrome is a diagnosis given to people with rising weight, rising blood pressure and blood sugar, and increasing cholesterol. Metabolic syndrome rose 22% from year 2000 to 2010 and continues to be the biggest health challenge in America. Health reports show that the rise in gout and uric acid tracks hand-in-hand with these same increases. The rise in HFCS consumption, the rise in obesity and the rise in Metabolic Syndrome are all linked. If we are looking for common threads then fructose has to be a major target.
Fructose has the following impact on your body:
- Lowers cellular energy – leads to greater fatigue
- Drives uric acid production - gout, kidney damage, and heart disease
- Drives kidney inflammation, kidney stones and high blood pressure
- Promotes fat storage and weight gain
- Increases risk of diabetes - increases insulin resistance
- Cholesterol problems – lowers valuable HDL while increasing triglycerides
- Appetite increase and leptin resistance
Summary of the WORST sources of fructose:
- Drinks – very dangerous as they are RAIDLY absorbed: Fruit juice, soda pop, Gatorade and sport drinks.
- Fruit, dried or fresh. Dried fruit is PURE fructose.
- Honey, yogurt, or fruit flavored desserts like pies
- Sauces, salad dressing, BBQ, Ketchup, and condiments
- Baked goods: bread, crackers, rolls, and bagels. Made with HFCS
Sorry if this news sours your precious fruit smoothie but you now understand that excess fruit and exposure to HFCS is quite deadly. If you must have fruit then choose berries as they have the least amount of fructose and lowest carb count. Avoiding all packaged foods also cuts out a tremendous amount of harmful HFCS. Ideally we don't want to consume more than 10 grams of fructose daily. See the fructose chart listing of fructose content in common foods. Get your lab test done to assess your current uric acid level and strive to keep this number under 5.5 for ideal health. As uric acid levels rise above 5.5 we begin to see adverse effects so don’t wait for gout to arrive before taking action.