Last week I shared a post from Harvard mildly criticizing intermittent fasting as a weight loss approach for the obese population. This week, I’ll discuss the highlights of Harvard’s The Nutrition Source, “Diet Review: Intermittent Fasting for Weight Loss”.
Now, the review itself is pretty short so this will be a short IF chat. Also keeping in mind that most of the critiques out there refer to IF as an approach for weight loss. For me personally, weight loss is not a goal, and I don’t fit into the obese category. So in the coming weeks, I am going to focus more on finding research about IF in relation to other health outcomes and try to find the longest, most interesting, human research studies.
The Nutrition Source review first describes a few methods of IF and the origin of the philosophy behind IF. Then they provide an overview “of the research so far”, stating that:
- IF supporters believe that the diet causes physiological stress which leads to an immune response that repairs cells and produces positive metabolic changes (reduction in triglycerides, LDL cholesterol, blood pressure, weight, fat mass, blood glucose)
- Studies have shown that people following IF do not tend to overeat during feeding times to compensate for calories lost during fasting times
- A systematic review of 40 studies found that IF was effective for weight loss, with a typical loss of 7-11 pounds over 10 weeks
- Of these, a drop out rate of 0-65% was seen among participants, regardless of whether they were following IF or continuous calorie restriction
- 12 studies compared IF directly to continuous caloric restriction and there were no significant differences in weight loss or body composition between the two groups
- One randomized controlled study following 100 obese women for the course of one year found no differences between the IF and continuous caloric restriction groups for any of the following:
- Weight loss, weight regain, or body composition
- Blood pressure, heart rate, fasting glucose, fasting insulin
- The dropout rate was higher in the alternate-day fasting group (38%) than in the calorie restriction group (29%)
In addition to the pitfalls previously discussed, the authors cite that prolonged IF may lead to disordered eating patterns such as anorexia. They finish with posing the following unanswered questions:
- How often, for how long should one fast to see therapeutic benefits?
- Is this diet safe and beneficial for everyone (e.g., generally healthy population, higher risk individuals with chronic diseases, elderly)?
- What are the long-term effects of intermittent fasting?
- Is there a risk of negatively influencing the dietary behaviors of other family members, especially in children who see their parents abstaining from food and skipping meals?
These are interesting questions, especially the last one. The second question seems fairly obvious because there is no *one* diet that is beneficial for literally everyone. As this review was published in 2017, it would be interesting to see an updated review from The Nutrition Source as more research is published. I’ll keep my eyes peeled.
Week 6 in review:
As I began to think this week about the 8-hour eating window days ahead, I found myself skipping breakfast altogether and adding my smoothie to lunch. I’m not 100% sure if this was the cause of, not just a correlation to, the fact that my 12pm workouts felt much, MUCH, better. I hit my strength goals every day this week with >80% of my 1 rep max (1RM) for 5 sets of 3 reps each for back squat (155#, should have been 148# according to 185# 1RM), deadlift (210#, should have been “205#” according to 260# 1RM, but could have done even more); power cleans (105#, should have been 85# according to 120# 1RM)… and all the lifts felt good. So now I’m actually pretty excited for 16:8, and at the end of this year this could be my chosen lifestyle. Let’s not get ahead of myself.
- The only challenge during the week was on Thursday (Valentine’s Day) when I said “to heck with it” and had a second glass of wine (past 9:30pm) while watching “My Big Fat Greek Wedding” on the couch, with my cat (#singlelady #valentinesday)
- I also worked my way through a small bag of peanut m&ms which were given to me on Thursday. Luckily, I was able to exercise enough self control to portion them out over 4 days
On Sunday, I made dinner for a date. It was my first time cooking for this gentleman, so I wanted to impress him. It was also an opportunity to make extra food for meal prep / eating leftovers during the week. And of course, in the spirit of Valentine’s Day, I wanted to bake something sweet.
On the menu:
- Massaged kale salad with carrots, toasted hazelnuts, dried cranberries, roasted butternut squash, garlic; lightly dressed with a lemon vinaigrette (lemon juice, olive oil, salt, pepper… massaged the kale then saved the rest)
- Duck confit pasta with fresh fettuccine (Food & Wine)
- The store didn’t have pappardelle so I used fettuccine instead
- Duck confit is expensive… next time I would probably just buy duck legs and make the confit myself in advance
- “Heartbeet” chocolate cake (via Bon Appetit)
- I used 1 cup almond flour and 1/2 cup arrowhead mills gluten free flour blend, since I had these on hand already
- Instead of buying completely fresh beets, I used pre-cooked beets from Trader Joe’s and saved myself 40 minute
- This cake. Is. Delicious.
Week 7: Adjusting to 16:8
We already know that the biggest challenge will be weekends. Weekdays, as long as I plan them per usual, should be successful per usual. I plan to continue the 1:30pm-9:30pm window which felt pretty great last week.
As I’ll be eating eggs, salads, and smoothies for lunch, then leftover pasta and salads for dinner, my grocery list this week consisted of things I needed for dinner on Sunday evening, and the usual suspects (bananas, spinach, soymilk, green goddess dressing).