Intermittent fasting or IF (fasting for 16 hr/day with an 8 hr feeding window), is something that has come and gone in the popular fitness magazines, but does it work?
Fat Loss
I will be up front with you. I have found zero evidence in the scientific literature that intermittent fasting is superior than any other style of dieting when Calories are matched. Before you get mad at me, I didn't say IF doesn't work. I said it isn't superior. That said, you should probably keep reading.
Muscle Hypertrophy
IF does have some benefits, but hypertrophy (muscle growth) isn't one of them. If you are looking to maximize muscle, 3-5 feedings of protein/day seems to be most optimal based on current research. With IF, you'd only be getting 2.
Health Benefits
Now that I've spent the first half of this article telling you all the bad about IF, let me tell you the good. IF and CR (caloric restriction) can actually help prevent Alzheimer's and Parkinson's diseases in older adults. "There are multiple interactive pathways and molecular mechanisms by which CR and IF benefit neurons including those involving insulin-like signaling, FoxO transcription factors, sirtuins and peroxisome proliferator-activated receptors. These pathways stimulate the production of protein chaperones, neurotrophic factors and antioxidant enzymes, all of which help cells cope with stress and resist disease." [1]
One study showed that a group of mice subjected to IF had significantly lower blood glucose concentration than the group that was eating whenever they wanted. [2]
Adherence
Adherence is actually the reason I wrote this article to begin with. One of the biggest reasons people fail to adhere to their diet, is being hungry. You've probably been told the classic advice, "You have to eat six times/day if you want to lose weight" but there's a major problem with this philosophy. You are already eating a lot less Calories than you are used to eating. If you take that reduced number of Calories and spread them over two times the number of meals you are used to eating, you're going to have tiny meals that aren't going to keep you full.
When our stomachs stretch, they slow the release a hormone named ghrelin. (Grehlin is released when our stomachs are empty. It goes up to the hypothalamus and tells our brain we are hungry.) Because of this, if we eat the same amount of Calories spread across fewer meals, we will feel more satisfied.
Most people work during the day. Because we are so busy working, we tend not to think as much about food. The opposite is also true. When we are at home sitting on the couch at nighttime, we tend to think a lot more about food. If we've already spent 83% of our daily Calories at this point (5 out of 6 meals), our last meal isn't going to be very satisfying. Have you ever gone to bed hungry? It isn't fun, is it. IF let's you eat much bigger meals when you do eat, making the reduced Calories less noticeable.
Practical Application
IF can be very beneficial to a diet from an adherence standpoint, but suffers because of it's distribution of protein over only two meals. I suggest a modified IF protocol. Open the feeding window up to 10-11 hours and eat 3-4 meals. The first meal will be only protein (probably a shake). The next meal (or 2) will be slightly larger, but still consist of mostly protein. The last meal will be your largest meal and consist of up to 50% of your daily Calories. This will allow you to eat an actual meal with your family and go to bed full. As an added benefit, carbohydrates before bed stimulate the production of serotonin so you should sleep better, too. Keep in mind, that is not an exact protocol for you to follow. It is a framework for you to play with.
Takeaway
As I have said many times before, the number one determinant of fat loss is actually being able to adhere to a Caloric deficit. If intermittent fasting helps you stick to your diet, do it. If it doesn't, don't do it.
Thanks for reading! I will be back with another fat loss topic next week. As always, God bless you AND your family! I'll talk to you next week.
References:
[1] Martin, B., Mattson, M. P., & Maudsley, S. (2006). Caloric restriction and intermittent fasting: Two potential diets for successful brain aging. Ageing Research Reviews, 5(3), 332–353. http://doi.org/10.1016/j.arr.2006.04.002
[2] Anson, M. R., Guo, Z., Cabo, R., ... Mattson, M. P. (2002) Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Proceedings of the National Academy of Sciences of the United States of America, 100(10), 6216-6220, doi: 10.1073/pnas.1035720100
