Intermittent Fasting Used As A Weight Loss Tool – We all know that weight loss is one of the top five New Year’s resolutions every year, and with that, a new diet fad seems to emerge. Intermittent Fasting seems to be all the rage this year — but is it just another fad diet? What is it and does it work for lasting weight loss?
Intermittent Fasting (IF) is a diet method that is designed to restrict caloric intake. When you fast (not eating or eating only very little for more than 12 hours), your body shifts to use energy stored in the blood (sugar and triglycerides), liver and muscles (glycogen or sugar), and fat.
Alternate day fasting, 5:2 (fasting two days each week), and daily time-restricted feeding (ex. Eating during only 6-8 hours of the day) are all different regimens of IF. On fasting days, calories are typically restricted to 500 calories or less.
On non-fasting days, you eat as you regularly would. Theoretically, restricting intake on the fasting days could make your energy balance negative (you’re eating less calories overall) and therefore, would make you lose weight. But is that really the case?
Animal and human studies of intermittent fasting have provided mixed results on weight loss. Some animal studies show that fasting can help rodents to lose weight and retain muscle mass (i.e. their metabolism doesn’t slow down). However, human studies have yet to provide solid evidence of significant, long-term weight loss with IF.
Some studies show only a very small weight loss with IF in humans, but these studies are often small and warrant more research before we can say that is effective for long-term weight loss. Other studies conclude that the weight lost with IF is about equal to the amount lost with a typical low-calorie diet.
Like any diet, IF can be challenging to adhere to. In the beginning, many participants express extreme hunger, cravings, headaches, and feelings of wanting to overeat when they aren’t fasting. Typically, these symptoms fade over time, but it may take a few weeks to notice a difference.
Some studies show that on non-fasting days people tend to make up for the lack of calories during fasting, and therefore aren’t meeting an overall calorie deficit. Biologically, skipping meals can slow your metabolism, which can result in storing more fat when you do eat, however this hasn’t been observed with some IF regimens.
While intermittent fasting is proving to be an efficacious method for changing the biochemical landscape and promoting weight loss, evidence is lacking on if these changes are sustainable. Therefore, it is still important to consider IF a tool amidst a healthy dietary lifestyle. Strategies that can support IF and sustainable weight management include:
- Replacing sugary beverages and alcohol with water or a variety of sparkling waters.
- Aiming for at least three servings of non-starchy veggies every day.
- Choosing to cook at home more often and limiting dining out to 3 or more occasions each week.
- Choosing whole foods and limiting processed foods
- Include lean proteins with meals and snacks to help with satiety and satisfaction
- Enjoy indulgent treats mindfully and less often
- Find healthier alternatives to eating when stressed or bored
- Sleeping 7-8 hours per night
- Move more by incorporating more physical activity (activities of daily living) and exercise (planned physical activity at a greater intensity.
There continues to be mounting evidence for calorie restriction and health benefits. Some proposed benefits of calorie restriction and IF include improved diabetes or insulin sensitivity, decreased risk for cardiovascular disease, delayed aging processes, reduced cellular stress, and delayed cognitive degeneration.
IF may be one way to restrict calories but might not help you to achieve caloric restriction if it’s done inappropriately. If you are interested in weight loss or dieting, it is highly encouraged to work with a Registered Dietitian to ensure safety, to meet your personal needs and provide accountability for meeting your goals!