The latest craze in dieting isn’t about eating certain foods, it’s about eating no foods – for a while, at least.
Intermittent fasting, during which dieters forgo food for various lengths of time, has become the diet du jour. But fasting itself is not a new phenomenon.
Abstaining from food has been done for centuries for many different reasons by many different cultures, but in the information age, it has become a widespread strategy for losing weight.
As the name suggests, intermittent fasting incorporates various periods of fasting and non-fasting. The three most popular forms that I see with my Copeman Healthcare clients include:
1. Feeding window — fasting for 16 to 20 hours and eating within a 4 to 8-hour window, most commonly between 12:00 and 8:00 pm every day.
2. The 5:2 — fasting for a full 24 hours for 2 days per week, and then eating on a regular schedule for the remaining 5 days.
3. Random meal skipping — assuming a typical three-meal plan with no snacking, one meal is skipped each day, usually alternating the skipped meals from day to day.
Does intermittent fasting work for weight loss?
Absolutely, intermittent fasting can, and probably will, help you lose weight. The caloric restriction that results when you skip meals or restrict the amount of time you eat will most likely create an energy deficit, leading to weight loss.
Of course, any diet that helps you restrict calories will almost always help with weight loss.
For example, a recent study that compared one group of intermittent fasters using the 5:2 method with a group of non-fasting dieters that ate the same amount of calories with no time restriction found there was no difference in the weight lost between the groups.
However, that same study also found that the participants taking part in intermittent fasting reported higher hunger scores than the group on a non-fasting diet. In my experience, if you are hungry day after day while on a diet, the chances of being able to follow your diet in the long term dramatically decrease.
Can intermittent fasting improve overall health?
Outside of weight loss, there have been some preliminary studies on mice that have shown that intermittent fasting has the potential to improve lipid levels and extend life independent of weight loss. With that being said, this potential means little to nothing until it can be demonstrated in human studies.
Depending on which type of fasting you choose, there are potential risks of dehydration and constipation, as well as nutrient deficiencies. So if you’re thinking of trying intermittent fasting, consult your dietitian to discuss the best approach.
What diet is the best diet?
Alas, there is still no solid evidence that there is one diet to rule them all. Comparative diet studies have shown no difference in weight loss between some of the most popular diets (e.g., low-carb, low-fat).
To that end, any diet that you can adhere to long term and that you enjoy is the diet you should be aiming for when considering a weightloss approach.
Remember, when you do decide to try a new diet, ensure you run it by your registered dietitian to prevent any nutritional faults or gaps.
I would not recommend intermittent fasting for someone living with diabetes, specifically the meal-skipping variety, as it has been shown to increase blood glucose after eating and may increase chances of hypoglycemia when using certain diabetes medications.