A good friend of mine who has battled weight gain for years decided to try the trendy diet called intermittent fasting (IF) to accomplish this goal. His aching knees, a bad back, and a recent type 2 diabetes diagnosis were factors in this leap of faith decision.
Over the years, he had battled his weight by bouncing from one fad diet to the next, with little to no success of keeping the weight off for good. But, this time has been different. So far, intermittent fasting has been the only trending weight loss diet that long-term, has kept him from regaining the weight he has lost.
Why intermittent fasting?
Hear the word “fasting” and most of us roll our eyes believing it to be another gimmicky diet. And many times they are. However, intermittent fasting has become a very popular and more mainstream method being embraced not only by celebrities but more importantly, healthcare professionals. And there is a growing body of research suggesting that cycling low-calorie days into your normal eating pattern may be good for not only losing weight but also your health.
It appears many individuals have had good luck with this dieting method. But is IF an effective, safe, and scientifically studied approach to achieving a healthier body weight, and can it help keep the weight off for good?
What is intermittent fasting?
Intermittent fasting is considered occasional starvation but done in a strategic manner. The idea is to cycle between periods of regular eating and fasting, during which you severely restrict your calorie intake. Some people fast for hours, while some may go for a full day or longer.
There are several different methods that can mean “intermittent fasting” but the most popular two are the “5:2 approach” or the “16:8 approach” If using the 5:2 approach, this refers to limiting calorie intake – to about 500 calories a day – for two days a week. The 16:8 approach is where you would only eat within an eight-hour window most days of the week and then fasting for the remaining 16 hours – e.g., eating only from 10 am to 6 pm.
Enthusiasts of this diet hypothesize that these periods of fasting help to lower insulin levels, leading to metabolic advantages in that fatty acids will be released from adipose or fat stores using up fat for energy. Since fasting is intermittent, it should not cause your metabolism to decrease or slow down. However, if a person fasted for longer periods of time, then that could slow down the rate of calories burned.
Pros of intermittent fasting
- Eating less will result in weight loss – Limiting the number of hours of eating during the day reduces calorie intake and discourages “grazing” all day and into the evening. When compared to diets focusing on increasing protein or fat but not necessarily reducing calories, IF may be a better way for some people to lose weight. Besides, IF makes intuitive sense. Food is broken down by enzymes in the gut. Take carbohydrates for example. Carbohydrate foods, such as white flour or rice, are quickly broken down into sugar, which the cells use for energy. Any sugar not used by cells will be stored in fat cells as fat. When we avoid eating for long stretches in IF, insulin levels go down and this allows the fat cells to release their stored sugar to be used as energy. Thus, weight loss occurs since insulin levels are kept at lower levels for longer amounts of time helping the body burn off fat.
- You are not starving yourself – Many people equate “fasting” with starvation or drastically reducing calories for days and days. IF is more about cutting back on calories for short periods of time affecting hunger and cravings over time. As your body adjusts, you become satisfied more easily with smaller portions. Choosing healthy foods helps reduce cravings for unhealthy foods, such as those loaded with refined sugars.
- Fasting may improve your overall health and extend your life – This is likely due to the ways that it affects cell and hormone function, according to several studies. In one recent study, periodic fasting was linked to lower risks of heart disease, diabetes, cancer, and aging.
- May improve blood lipid levels – Some studies on IF have shown it may decrease low-density lipoprotein (LDL) or “bad” cholesterol, as well as inflammation. Additionally, IF may improve insulin resistance, which in turn, helps stabilize blood sugar levels.
Cons of intermittent fasting
- “Rebound effect” – Shortening the “window of time” you are eating during the day, may lead to eating more during your “window of eating opportunity.” For instance, if you’re eating hours are between 10 am to 6 pm, you may make up for not eating breakfast by eating more at lunch. Or if you follow the 5:2 approach where you eat only 500 calories two days a week, you may overeat on the other days you are not fasting. Therefore this “rebound effect” can wipe out any benefit of fasting, unless carefully monitoring what you eat.
- You may feel fatigued – Food is what gives us energy and when we cut back on calories or the window of time for eating, this can result in more fatigue and difficulty in concentrating during the day.
- Long-term use is questionable – We are always searching for that one perfect method for weight loss that is relatively easy and doesn’t require us to give up the foods we love. IF seems to fit this requirement. But if we find ourselves very cranky and hungry on the days we are to eat only 500 calories or maybe we don’t want to eat only during certain hours of the day, sticking to a fasting diet may not be feasible or realistic long term. You could probably do IF for a few weeks or even months, but for the rest of your life is unlikely.
There is no one-size-fits-all fasting diet. The best and most effective diet plans are highly individualized. While IF may aid weight loss, it’s not a practical or sustainable plan for everyone.
IF can be effective for some people for getting a jump start on weight loss, many of us can simply make smart lifestyle changes such as focusing on eating more vegetables and fruits and choosing other health-promoting foods.
Other things to learn from IF include:
- Avoid sugars and refined grains. Instead eat fruits, vegetables, beans, lentils, whole grains, lean protein, and healthy fats (essentially, a sensible, plant-based Mediterranean-style diet).
- Let your body burn fat between meals. Avoid snacking. Be active throughout the day and build and maintain muscle tone.
- Consider a simple form of IF. Limit the hours of the day when you eat and for best effect, eat the majority of your calories early in the day and avoid eating after your dinner meal.
IF is not intended for people with advanced diabetes, those using insulin or who are on medications for diabetes, people with a history of eating disorders like anorexia and bulimia, and pregnant or breastfeeding women should not attempt intermittent fasting unless under the close supervision of a physician who can monitor them.
Overall, you have to consider how IF may affect you and for anyone with health issues, they should consult with their doctor if IF would be right for them.