When carbohydrate consumption falls below 100 grams, the body usually responds by burning muscle tissue for the glycogen (stored glucose) it contains. When those glycogen stores start to run out, the body resorts to burning body fat. But that’s a very inefficient, complicated way to produce blood sugar. The body tries to do it only when it absolutely has to (such as when it’s starving)—and for good reason. Turning fat into blood sugar comes at a price in the form of by-products called ketones. They make your breath smell funny. They can also make you tired, lightheaded, headachy, and nauseated. Feeling lousy is certainly one way to dampen the appetite, but not one that most people would choose.
In a 2 (monitoring vs. not) x 2 (restricting vs. not) fully crossed, controlled experiment, 121 female participants were assigned randomly to one of four dietary interventions for 3 weeks. The monitoring + restricting condition tracked their caloric intake and restricted their caloric intake (1200 kcal/day); the monitoring only condition tracked their caloric intake but ate normally; the restricting only condition was provided 1200 kcal/day of food but did not track their calories, and the control group ate normally and did not track their intake. Before and after the interventions, participants completed measures of perceived stress and 2 days of diurnal saliva sampling to test for cortisol.
One of the most common mistakes is avoiding saturated fats for fear they will worsen a patient’s cardiovascular health. Nothing could be further from the truth. In fact, studies continue to pour out of the scientific literature confirming that your dietary intake of saturated fat does NOT impact your blood levels. In fact, the study goes on to show that carbohydrates are the real culprits (if you are overweight or out of shape), increasing blood levels of saturated fats alongside a key marker associated with insulin resistance, metabolic syndrome, and type-2 diabetes. 11 In short, cut the carbs to get your health and bodyweight back on track.