@bkolden asked about my opinion on exercising on a fasted state. In summary, I do not recommend doing workouts, long rides or events on a fasted state.
Please see this post for an overview of this topic.
Below are links to the several position papers, all of which have in common the recommendation that athletes practice adequate energy intake for intense training and competition:
American College of Sports Medicine position stand. Nutrition and athletic performance.
International society of sports nutrition position stand: nutrient timing.
A more recent study that looked at several other studies on the subject of fasting and endurance sports concluded that:
" This review of the literature identified that the effects of fasting on endurance athletic performances requires further investigation. Different fasting programs influences human physiological and biochemical parameters that are important for athletic performances. The collective data suggest that different fasting practices (ICR, ADF and TRF) decrease body weight and fat7,27 in both trained and untrained subjects. Moreover, several studies demonstrated that fasting alters protein, lipid and glucose metabolism and associated hormonal responses. However, the conflicting findings related to glucose metabolism in response to fasting in highly trained athletes require further investigation. Studies on the effects of fasting on indicators of physical performance have generated conflicting data. For example, some studies reported decreased performances while others showed no effect. There are a number of reasons for such differences, including variations in experimental design, fasting duration, and unique participant characteristics. We suggest that athletes train at relatively low intensities (and not at high intensity levels) when fasting to ensure that they recover adequately to optimize performances in competitive events. Our analyses also revealed a major weakness in that most fasting studies recruited sedentary subjects or low-level athletes, often without well-matched controls. We recommend that well-controlled studies are required to improve our understanding of the effects of exercise in fasting athletes, and to help uncover novel insights into the mechanisms driving changes in energetic pathways and physical performances in trained endurance athletes that choose to fast."
Aside from studies, here are a few articles from popular media:
Why Intermittent Fasting is Worthless for Endurance Athletes
It never made much sense to me, but then I’m much more of an all things in moderation kind of person. I just always feel better with 3 meals, and the last year have tried to push to far less empty calories and carbs in favor of healthy options. For example, I’ve maintained a weight loss that was initially obtained through heavy reliance on capping calories to now just eating way more veg and smaller portions of carbs. I’m a vegetarian (eat dairy and eggs, though in smaller quantities than I used to). So for me, a breakfast with some protein and whole grain carbs is essential before any efforts! Don’t think I could ever go full vegan, but gosh do I feel better since reducing my intake of cheese in favor of more plant proteins.