Intermittent fasting seems to be gaining in popularity and some people have been getting great results with it. There are a number of different strategies, such as; eating regularly for 5 days of the week and eating next to nothing for 2 days, or fasting for 16 to 20 hours of each day and only eating in a short window of time.
There are no magic tricks though, some people just find it easier to eat less in a day (or overall in a week) when they have set times when they can and can’t eat. The most important thing in terms of our weight is how much we are eating and drinking each day, not the actual times we are eating. The underlying principle of body weight management is energy balance. The amount of energy we consume in a day versus the amount of energy we burn in a day. It is totally fine to look at energy balance with a weekly average too. Calories are the unit of measurement for energy. Weight loss requires a Calorie deficit (consuming less energy than we burn) and weight gain a Calorie surplus (consuming more energy than we burn).
Intermittent fasting, whether we are talking about fasting for certain days of the week or certain periods of each day, can be beneficial for many people aiming to create and sustain a Calorie deficit for weight loss. However, reviews of numerous research studies conclude that whilst fasting is a viable strategy for weight loss, it is not superior to creating Calorie deficit through other means, such as monitoring Calorie intake but eating throughout each day.
Having rules around when one can and can’t eat might help people eat a little less each day, especially if they are prone to snacking/grazing. It means the window in which they allow themselves to snack is much shorter. It can also help to show people that dealing with a bit of hunger is possible and we don’t need to be eating at all points of the day.
However if you eat the same amount of food between 12pm and 7pm as you would between say 8am and 7pm it will not make any difference to your body weight.
Fasted cardio is another linked strategy which is believed to be a winning combination for weight loss. Not eating anything before doing some form of exercise in an aim to burn more body fat. Again, through scientific research, we see that fasted cardio is not superior to simply managing the amount of energy being consumed and burned each day. When study groups consumed the same amount of Calories, it made no difference to fat loss whether the first meal was before or after exercise.
There are also conflicting ideas about when is the best time to eat when using a fasting strategy. There is research showing greater weight loss when most food intake is in the morning. However there is equally as much research showing greater weight loss when food intake is skewed towards the evening. The greatest influence on the results appears to be personal preference and to what an individual can adhere. Tuning into your appetite can help you develop the best strategy that works for you. If you are not often hungry in the morning, but feel ravenous in the evenings, it would likely suit you to eat most of your food in the evening. And if you are hungrier in the mornings than evenings, the same applies in reverse.
There are some loud voices in the nutrition world encouraging everyone to practice fasting due to improvements in autophagy (turnover of cells), inflammation and other markers of health. However research has shown that weight loss by any means improves these markers and the maintenance of a healthy body weight is just as influential. Again, finding the best strategy for you personally, to reduce and maintain a healthy body weight long term is the key.
With any nutritional strategy, we believe it’s important to consider whether it is a sustainable long term approach. Do you see yourself continuing with his strategy for years, even lifelong? If the answer is no, then it might not be the best strategy for you.
You can practice intermittent fasting without having hard rules about the times you can and can’t eat. If you are not hungry in the morning, you don’t have to eat. Some days you might be hungry and choose to eat earlier than other days. Some days it might suit you and your body more to eat in the morning, especially if exercise performance is a consideration. If you can listen to your appetite and eat accordingly, this may mean that you actually fast some days whilst other days not.
For muscle building specifically, intermittent fasting is likely to be sub-optimal. To optimise muscle growth, we ideally want to spread protein intake throughout the day. By restricting times in which we are consuming a protein rich meal, we may not be optimising our muscle growth potential. Current recommendations from the Journal of the International Society of Sports Nutrition (JISSN) are to spread protein intake across at least 4 meals to maximise muscle growth potential. To do so whilst restricting the times in which we eat through fasting is unlikely to produce optimal results.
In conclusion, consider your goal, your preferences and how you like to eat. Fasting absolutely may suit you personally and even if not completely optimal for your goal, might still work in your favour if it helps you maintain a consistent eating schedule and consume the appropriate amount of energy for your goal.
Not sure if you can do it forever but are interested? By all means try it. We just suggest that you don’t give yourself rules which are too strict and encourage you to try fasting in conjunction with listening to your appetite and developing a way of eating which you enjoy.
If you’ve tried fasting but it didn’t work for you, don’t feel like you failed. It was the strategy that failed you and there are plenty of other viable fat loss strategies.
If you would like to learn more about nutrition and how you can find a way of eating that suits you, contact today.