I went to the gym this morning for what my husband calls “double potions” — spin class followed by a muscle-mix session with free weights. His joke is a reference to the class timetable for Gryffindor House in Harry Potter and the Philosopher’s Stone, which included a double-length class for potions once a week.
I know very well that neither physical activity nor calorie reduction, nor both together, are the magical answer for reversing obesity or maintaining long-term weight loss. Those approaches all win in the short term, sure. But then they fail, even after a year or two of diligent adherence because the human body is programmed to return to the previous metabolic set point. I’ve lived the reality of this metabolic adaptation for decades. I’m not obese, but I keep chastising myself about that same 10-15 pounds that I lose and put back on again. I am still looking for an answer to fix things for good.
Can the metabolic set point be reprogrammed?
That’s the million dollar question. I recently read The Obesity Code by Jason Fung, MD. It’s an excellent read and not your average diet book. Dr. Fung is a nephrologist (kidney specialist) and founder of Intensive Dietary Management in Toronto, Ontario, where he specializes in treating people with type 2 diabetes and obesity. I loved his humour and found myself laughing out loud in several spots.
Dr. Fung writes that there are multiple overlapping pathways to obesity. The common uniting theme is too much insulin. Obesity is a hormonal disorder of fat regulation. To lower insulin and insulin resistance, we must address both what we eat and when we eat.
Most of the “what to eat” advice sounded familiar:
- reduce consumption of added sugar
- increase healthy fats
- eat lots of the right kind of carbohydrates e.g. vegetables and fruit
- limit refined carbohydrates
- choose unprocessed food
- don’t overdo protein consumption, since protein can also increase insulin, even though not as much as refined carbohydrates
- maximize protective factors, like fibre and vinegar (Note: I am not sold on the vinegar recommendation.)
But for me, the advice about “when to eat” was new:
- just don’t snack – “a healthy snack is one of the greatest weight-loss deceptions.” All day grazing leads to constant insulin response stimulation and excess fat storage.
- make breakfast optional – it’s a myth that we need to eat a hearty breakfast to ensure eating less the rest of the day
- fasting to create periods of very low insulin are beneficial
Intermittent fasting to combat obesity
Intermittent fasting has been gaining popularity and seems to be working for many people. When we fast, glucose is not available for energy, so the body switches to using fat instead, without any detriment to health. Throwing the switch from short-term glucose burning to longer-term fat burning happens with fasting periods of 24 to 36 hours.
Contrary to what we might first think, fasting increases metabolism: “As food intake goes to zero, the body switches energy inputs from food to stored food (fat). This strategy significantly increases the availability of “food” which is matched by an increase in energy expenditure,” writes Dr. Fung. Studies found that eating a single meal per day led to significantly more weight loss and no evidence of muscle loss when compared to eating three meals per day, despite the same caloric intake.
Throwing my body’s metabolic switch by fasting might just be the magic I’m seeking.
In The Obesity Code, Dr. Fung provides two suggested templates for fasting protocols:
- 24-hour alternate daily fasting protocol: on fasting days, skip breakfast and lunch and have a light dinner; and eat smart on non-fasting days
- 36-hour alternate daily fasting protocol: on fasting days, skip breakfast, lunch and dinner; and eat smart on non-fasting days
For both protocols, snacking is prohibited, and it’s important to stay well hydrated with water, green tea, and coffee. Dr. Fung also suggests homemade, salted bone broth in place of lunch on fasting days to maintain sodium levels.
Note that fasting may not be right for you, especially if you have diabetes or a metabolic disorder. If you are interested in making changes to your diet, make sure to have a discussion with your physician or healthcare provider first.
Have you tried intermittent fasting to unlock your obesity code? If so, how has it worked for you? I may give it a try over the summer months.
Check out Caitlin Kelly’s recent excellent post about her fasting experience: The Challenge of Intermittent Fasting.
Fasting Diets Are Gaining Acceptance: Anahad O’Connor, The New York Times, Well. March 16, 2016
Scarborough doctor’s book says insulin makes you fat, fasting makes you thin: Michele Henry, The Star.com, January 25, 2016
Intermittent fasting, done right, can lead to weight loss: Leslie Beck, The Globe and Mail, June 15, 2015