If you take a sugared drink while eating meat, the animal protein reduces your ability to burn off the calories from sugar by more than a third (BMC Nutrition, July 20, 2017). In this elegant new study, 27 healthy-weight adults spent two full days in a sealed "metabolic room" that measured how many calories their bodies burned each minute by tracking their intake of oxygen and outflow of carbon dioxide and measuring calories lost in their urine. On both days they took in exactly the same total calories, protein and fat in two meals. However with one meal, they drank a sugary cherry-flavored drink and the other meal with an identical-appearing-and-tasting sugar-free cherry drink, so the only difference was whether they drank a sugared or a sugar-free drink. The sugared drinks caused the subjects to burn eight percent less fat. When the amount of animal protein was doubled, they burned even less fat with the sugared drinks (7.2 grams vs 12.6 grams).
You can store an almost infinite amount of fat in your body, but you store very little sugar only in your liver and muscles. When you take in sugar with a meal, you burn the sugar first and spare the fat. Any extra sugar that you take in that is not burned immediately is converted to fatty triglycerides that quickly fill up your fat, liver and muscle cells.
An eight-ounce serving of a soft drink typically contains 96 calories, so every time you take a sugared drink with your protein meal, you are storing about 30 extra calories of fat in your body beyond what you would have burned if you didn't take the sugared drink. This means that if all else stays the same, taking a single sugared drink with a protein meal each day would add a pound of fat to your body in a little over three months. This is in addition to any extra calories that you take in and do not burn. A weight gain of three to four pounds a year can lead to considerable obesity, disease and suffering as a person ages.
Both Meat and Sugared Drinks Increase Risk for Diabetes
Many studies show that eating red meat reduces a cell's ability to respond to insulin to keep sugar outside of cells and blood sugar levels high (J Diabetes Res, July 9, 2015;174742). See Why Meat May Increase Risk for Diabetes. Eating animal protein at the same time you have any rise in blood sugar prevents sugar from being broken down inside cells and therefore causes blood sugar levels to rise even higher. Sugared drinks raise blood sugar more quickly than sugars in solid foods, so they increase risk for developing diabetes; see my report, Sweet Drinks Raise Risk for Diabetes. Sugared drinks include sodas, sweetened coffee, tea, energy drinks and all fruit juices.
More than 40 percent of all adult North Americans already have high blood sugar levels and therefore are pre-diabetic or diabetic. Signs of high blood sugar levels include having a protruding belly, having small buttocks and hips, and having a blood sugar level greater than 140 one hour after eating a meal. See The Hidden Epidemic of Early Diabetes.
If you are prediabetic or diabetic, or just want to prevent becoming pre-diabetic:
• Lose weight if you are overweight. I recommend intermittent fasting.
• Restrict refined carbohydrates. Most liver fat comes from added sugars and other refined carbohydrates.
• Restrict all sugared drinks including fruit juices.
• Restrict red meat, processed meat and fried foods that block insulin receptors.
• Eat plenty of vegetables, seeds and nuts which are rich sources of soluble fiber that helps to reduce insulin resistance (Clin Transl Gastroenterol, Jun 2016;7(6):e176).
• Try to exercise every day.
Note: This study does not endorse the use of artificial sweeteners and I certainly do not recommend them. See my latest report on Artificial Sweeteners . The researchers needed to use them to make the meals appear identical.