IF YOU WANT TO LOSE WEIGHT, THE FOOD amount that you consume appears more important than meal timing. Intermittent fasting did not appear to be associated with weight loss over six years. That is the finding of a study recently published in the Journal of the American Heart Association.
Intermittent fasting (IF) is an eating pattern in which individuals confine their food consumption to certain hours of the day. IF does not specify the foods you should eat; instead, intermittent fasting is about when you should eat them.
Common intermittent fasting methods include daily 16-hour fasts or fasting for 24 hours twice weekly.
Some evidence points to benefits associated with IF, including weight loss and improved heart and brain health. Intermittent fasting may even help one to live longer.
Today, we’ll look at intermittent fasting methods, how IF affects your hormones and cells, and end with the new study looking at intermittent fasting and weight loss.
“I’ve long believed that good food, good eating, is all about risk. Whether we’re talking about unpasteurized Stilton, raw oysters or working for organized crime’ associates,’ food, for me, has always been an adventure.”
― Anthony Bourdain, Kitchen Confidential: Adventures in the Culinary Underbelly
Intermittent Fasting Methods
While there are numerous approaches to intermittent fasting, all involve splitting the day (or week) into eating and fasting periods. The fasting periods are characterized by little or no eating. Some popular methodsinclude the following:
- The 16/8 method (Leangains protocol). Skip breakfast and restrict your daily eating period to eight hours (e.g., 1 to 9 pm).
- Eat-Sop-Eat. Fast for 24 hours, once or twice per week (e.g., fast from dinner one day until dinner the next day).
- 5:2 diet. Consume 500 to 600 calories on two non-consecutive days of the week and normally eat the other five days.
I infrequently use the 16/8 method, skipping dinner and restricting my eating pattern to eight hours (from 6 am until 2 pm the next day). While I am not trying to achieve weight loss, does the practice help a practitioner of intermittent fasting lose weight?
Intermittent fasting effects on cells
Fast, and you will see several changes on the cellular and molecular levels. Your body will change its hormone levels to make stored body fat more available.
Your body’s cells will also ignite vital repair processes and alter gene expression. Here are some of the adjustments induced by intermittent fasting:
- Insulin. Insulin sensitivity improves, and insulin levels dramatically drop. With lower insulin levels, the body makes fat more accessible.
- Human growth hormone (HGH). Intermittent fasting causes growth hormone levels to explode as much as five-fold. This change can help with fat loss and muscle gain.
- Cellular repair. With fasting, your cells begin the repair process; autophagy involves cells digesting and removing their old and dysfunctional proteins.
- Gene expression. Genes influencing longevity and disease risk reductionare altered by intermittent fasting.
These changes in hormones, cell function, and gene expression may translate to health improvements.
Intermittent fasting and weight loss
While calorie restriction benefits are clear in animal studies, we have less high-level evidence in humans.
Proponents of intermittent fasting note that IF causes those above hormonal and cellular responses, leading to metabolic improvements. The potential benefits include drops in triglycerides, LDL cholesterol, blood pressure, weight, fat mass, and blood glucose).
Some studies suggest intermittent fasting facilitates shedding pounds. A systematic review of 40 studies found that intermittent fasting facilitated weight loss, with a loss of seven to 11 pounds over ten weeks. However, this review included studies using a wide variety of fasting approaches, the participants differed (for example, lean versus obese), and the follow-up length varied.
Moreover, half of the studies in the review compared a fasting group with a control one, while the other half only had an intermittent fasting group. With all of that said, here are the findings:
- There appeared to be no differences in dropout rates when comparing fasting and continuous calorie restriction groups. The IF approach was not easier to follow than other weight loss approaches.
- For the 12 studies comparing fasting with continuous calorie restriction, there was no difference in weight loss amounts (or body composition changes).
- Ten trials examining appetite changes showed no increase in the intermittent fasting groups, despite drops in leptin (a hormone that suppresses appetite).
A new study
Johns Hopkins University (USA) asked 547 study participants to record (in a mobile app) their meal size and time of day when they ate. Using electronic medical records, the researchers analyzed each subject’s weight over six years, including at least five years before they began logging their meals and six months after.
The scientist separated the recorded meals into three categories:
- Small meals with fewer than 500 calories
- Medium meals with 500 to 1,000 calories
- Large meals with more than 1,000 calories
Not surprisingly, those who consumed the largest and medium meals gained weight over six years. Those eating fewer, smaller meals lost weight. Eating fewer calories was associated with weight loss.
Looking at meal timing, the researchers discovered this:
There was no association between weight change and intermittent fasting (limiting food intake to a specific time window). In addition, there appeared to be no link between weight change and the timing of an individual’s first meal after awakening or last meal (or snack) before bedtime.
In summary, changing the timing of eating did not prevent slow weight gain over many years. Study author Dr. Wendy Bennett remarked, “Probably the most effective strategy [for weight loss] is by really monitoring how much you eat, and by eating fewer large meals and more small meals.”
While the average person gains a pound or two per year (adding to significant weight gain over time), I dodge that problem by eating fewer large meals and more small meals. Ultra-processed foods (chips, soda, sausages) are usually verboten.
The current study continues the debate about IF and weight loss; we need better studies that are prospective and look at diet quality. I will end with this warning: Anyone with the following conditions should abstain from intermittent fasting:
- Diabetes
- Eating disorders involving unhealthy self-restriction (anorexia or bulimia nervosa)
- Use of medicines that require food intake
- Active growth stage, such as in adolescents
- Pregnancy, breastfeeding
The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider if you seek medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
Thank you for reading “Does Fasting Lead to Weight Loss? The Answer May Surprise You.”
