Your Health

Talk to your health-care provider before fasting to shed weight

Glucose monitor.
Photo of Kathy Ladd. KATHY LADD
Winnipeg Regional Health Authority
Published Friday, December 30, 2016

With New Year’s Eve just around the corner, it’s safe to assume that many Manitobans will soon turn their attention to coming up with resolutions to improve their lives over the next 12 months.

And, given that many people tend to overeat during the holidays, it’s also safe to assume that at least some of them will be making a resolution to shed a few pounds a top priority during 2017.

Of course, resolving to lose weight is one thing. Doing so is another.

As a registered dietitian, I tell my clients that the best way to maintain a healthy weight is to follow a healthy, balanced diet.

Generally speaking, this means eating three meals and healthy snacks every day to give your body the nutrients you need to maintain your health, feel good, and have energy.

Yet despite the evidence supporting these healthy eating practices, many people still feel the need to try various fad diets to lose weight.

The rising popularity of intermittent fasting to lose weight is a case in point.
Essentially, intermittent fasting is the practice of not eating during a specified time interval. During the fasting period, no solid food is eaten, but staying well hydrated with water, tea, coffee and soup broths is recommended. The most popular method is the 16:8 fast. It only requires trading breakfast for a cup of coffee (or some other non-caloric fluid) and having lunch as the first meal of the day. Fasting from 8 p.m. to 12 noon, for example, equals 16 hours of fasting. A 16:8 fast can be done as often as you like, such as twice a week, on weekdays only, or every single day. There are many other variants of intermittent fasting, including fasting for 24 hours (often dinner to dinner) once or twice a week. 

Proponents of intermittent fasting claim that it has many health benefits, including reducing inflammation, lowering blood pressure, lowering heart rate, lowering cholesterol, and reducing insulin resistance, as well as help prevent the development of Type 2 diabetes. Followers of the diet also believe that it can prolong your life and prevent Alzheimer’s disease.

But research to support these claims is limited. According to evidence from human studies, almost any intermittent fasting regimen can result in some weight loss. In addition, a small number of human studies show that fasting appears to result in reductions in insulin and glucose concentrations in the blood, improvements in lipid levels and reductions in inflammatory factors.

Animal studies show that intermittent fasting and restricting nighttime feeding reduces the risk of obesity, obesity-related conditions such as nonalcoholic fatty liver disease and chronic diseases, such as diabetes and cancer.
However, there is no published human data linking intermittent fasting with improved clinical outcomes for diabetes, cardiovascular disease, cancer or other chronic diseases. 

Although research suggests intermittent fasting does not pose any significant health risks for most people, some have reported side-effects, such as headaches and dizziness, nausea, and constipation. Adequate hydration, use of bouillon or salt in water and added fibre in the form of flaxseed or chia seed can help with these side-effects.

Nonetheless, growing children and adolescents, pregnant women and breastfeeding women should not do intermittent fasting, as they have increased nutrient needs. As well, it is not suitable for people who are underweight, and people who have an eating disorder. Also, anyone on medication, especially insulin, should discuss fasting with their doctor first.

Bottom line: While this approach may sound appealing to some, it’s important to remember that not a whole lot of research has been done in this area, at least with humans. Intermittent fasting regimens appear to promote weight loss and may improve metabolic health; however, there is insufficient data to determine the optimal fasting regimen, number of fasting days per week or recommendations for food intake on non-fasting days. If intermittent fasting is something you are considering, talk it over with your health-care provider first. 

If you would like to take a more conventional approach towards weight loss: eat a healthy balanced diet, avoid highly processed foods, sugary drinks and fast foods, drink water to satisfy thirst, and consume more vegetables and fruit and home-cooked meals.

For more information, call Dial-a-Dietitian at 204-787-8248.

Kathy Ladd is a registered dietitian at Health Sciences Centre Winnipeg. This column was originally published in the Winnipeg Free Press on Dec. 30, 2016.

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