There are far too many options when it comes to dieting for fat loss. (Remember the goal in to manage body composition and not just “weight”.) As well, the diet we follow for weight loss should be the same diet we follow for weight maintenance and weight gain (ideally, muscle gain). The only difference will be caloric balance—i.e., hypocaloric for weight loss, eucaloric for weight maintenance, and hypercaloric for weight gain. Among the options that are gaining popularity is “intermittent fasting”.
Intermittent fasting is basically just an approach to nutrient timing. There is a range of possible fasting to feeding ratios, and it really comes down to preference and what works for the individual. Perhaps the most common approach is 16-hour fast followed by an 8-hour feed. When it is considered that sleep is usually about 8 hours, then the dieter is looking at having to manage eight hours of hunger.
Intermittent fasting is essentially a variation of the “ketogenic diet” as it will force the body into a period of ketosis. As such, it can promote more rapid fat loss. One thing to consider is that fat loss comes from being hypocaloric. Thus, any diet that restricts calories will facilitate fat loss. (Conversely, overeating during the feeding periods will impact weight management.)
There are benefits to intermittent fasting, if one has a tendency to binge eat in the evening. One goes as long as possible without eating, leaving the bulk of the calories to be consumed in one of two meals. It is important for the dieter to realize that restricted feeding time does not mean unrestricted feeding. Calories count!
There are challenges with intermittent fasting. This is especially true for those who are exercising. While fasted cardio might promote greater fat loss, weight training fasted is less effective. Ideally, one looking to gain muscle and strength will consume protein and carbohydrate in relative proximity to training. For many of us, training times don’t coincide well with the principles of intermittent fasting. (Personally, I prefer to have a morning and afternoon training session. As such, intermittent fasting doesn’t work for me.)
If intermittent fasting doesn’t suit you, there is a compromise. For most, working a busy schedule it is a bit easier to “skip” eating through much of the day. I find a buttered coffee (1 T coconut oil and 1 T grass-fed butter; ~220 kcal) for breakfast can sustain me for quite some time. Once I get busy with my day, I don’t think much about eating. (Conversely, a high-carb breakfast will be higher in calories and leave the body screaming for a midmorning snack.) The less one eats during the day, the more that can be eaten at night, when most have the greatest tendency to binge.
Feeding while intermittent fasting should be the same balanced macro approach we would take in any “diet”—adequate protein (e.g., 1 g/lb) and mostly vegetables. “Premium” carbs should be limited for fat loss and on non-training days. One might prefer, then, to eat more “keto” during the feed. Whatever the macro balance, choose wisely. Crappy food is still crappy food, even when eating in a restricted time frame.
Bottom line? Caloric balance is half the battle. Keep calories in < calories out, and you should lose weight (fat). Intermittent fasting may help some keep the calories restricted.
Ideally, exercise should be fueled with some carbs and protein. This is not such a big concern for most (especially those of us looking for more general fitness). Food takes time to digest and be absorbed into the blood. Nutrients from the foods ingested during the restricted feeding time will take time to get to the tissues. Make healthy choices (i.e., choose high fiber and healthy fats) and nutrients will be available to fuel the body. Worry less about when and more about what you eat (in particular, how much).
Intermittent fasting need not consume your life to be effective. Work it in as it fits your schedule and preferences. For example, fast on non-training mornings or on days you know you are at high-risk for consuming high calories (e.g., days with planned social events, holidays, etc.). Have a more traditional approach to nutrient timing on hard training days to make sure that the workouts are effective and there is fuel for muscle performance and recovery. Like any diet, use it to your advantage. The goal in weight management should always be to keep body fat lower and muscle mass higher. If you aren’t hitting your targets, adjust.
Be your best today; be better tomorrow.
Carpe momento!