Intermittent Fasting - What, Why, How?
Its likely that most of us have heard the phrase intermittent fasting (IF) previously, but many may not know what it exactly is and what it involves. This blog will delve into the depths of IF, what it is, the studies behind it and how you can apply it to your life to live happier and healthier.
What is it?
Intermittent fasting is eating within windows of time and fasting for a set period of time. A common ratio of IF is 8:16. In essence, an eight hour window where you can eat and a sixteen hour window where you are fasting. Many people following this ratio will eat within the hours of 10am to 6pm every day. Whilst IF encourages eating healthy foods. The focus is on consuming a variety of foods to achieve a balanced diet, and this includes some ‘unhealthy’ foods too. Other forms also include alternate day eating or fasting completely for one day a week.
The theory behind IF is that by giving the body a break, the gut can rest and energy can be focused on other bodily systems such as the muscles and immune system. With this energy focused elsewhere, the body can do things such as exercise, repair tissues and grow.
Reported benefits, looking at the research:
Stable blood sugars
Reduced insulin resistance
Reduced inflammation around leptin receptor sites results in reduced leptin resistance which causes weight loss
Effective method to help portion control and frequency of food intake
There are many more reported benefits but not all have been effectively proven by research
Things to consider:
IF may be more effective than simple calorie reduction but it is necessary to ensure that you are still getting an adequate nutritional intake
Still possible to overeat during the window of food consumption
Could lead to hunger, irritability, poor concentration, tiredness, headaches and dizziness
Can reduce weight short term but currently no long term evidence
Studies don’t generally consider health, more weight focused
No optimum number of calories to reduce It is also not good for those who are pregnant, having an eating disorder or who are diabetic
How can to incorporate it into your diet:
As with anything, I recommend starting slowly. Begin with a wide window, for example eating within 8am-6pm every day. Cut out those midnight snacks and do this by ensuring you have eaten enough food during this time. Start to eat your meals at the same times each day, this way your body will start to prepare to digest food at the right time and focus on other bodily processes when outside your eating window. Slowly move from 8am to 8:30am to 9am and so on until eventually you achieve your desired time. I recommend no less than a six hour window, for example 12pm-6pm. Keep your diet relatively the same until you are in a set routine of eating. You may notice you begin to loose weight and feel lighter and healthier solely from changing your eating schedule. When you are happy with your schedule and you have set eating times, then you can begin to change the foods you eat or reducing the quantity of foods that you eat depending on your health goals (eating for health, weight loss, muscle definition and toning etc).
My personal schedule:
I wanted to give people an insight into how I eat, so I have included below my schedule. I currently eat 8am-6pm. Often I will eat 10am-6pm however I often feel very hungry following my morning workout and I listen to my body and feed it. I cant stress enough how important it is to get in touch with your body and its hunger signals and responding (and I don't mean eating whatever treats you feel like when you like).
6am - Yoga Workout and Meditation
8am - Morning Meal - something small such as fruit, smoothie, avocado toast or cereal
10am - Small Snack - ONLY if hungry, fruit, oat bar or sometimes this could simply be a glass of juice or decaf coffee
12pm - Lunch - largest meal of the day and usually a warm meal, such as pasta, curry, fajitas, roast dinner and so on.
6pm - Small Evening Meal - this may be a salad, bowl of fruit, tomatoes or avocado on toast, sandwich or even a small meal replacement shake
8:30pm - Gentle Yoga and Meditation
I try to make sure that I don’t eat anything following this evening meal or post 6:30pm. I have found since doing this I have slept better, had less nightmares, had easier digestion, regular bowel movements and no bloating! This is my own journey so these benefits may not necessarily happen in the same way for you. However, once you find the best way of eating or your body you should begin to see results too. Its not only about the type of food and exercise its about when you eat, how big your meals are and when in the day you exercise.
If you want any more information about how to apply this way of eating to your diet and lifestyle, please get in touch and I will happily schedule you in for an appointment.
Until then, Lottie x
Antoni, R., Johnston, K., Collins, A. and Robertson, M. (2016) 'Investigation into the acute effects of total and partial energy restriction on postprandial metabolism among overweight/obese participants', British Journal of Nutrition, 115 (6), pp. 951-959.
Antoni, R., Johnston, K., Collins, A. and Robertson, M. (2017) 'Effects of intermittent fasting on glucose and lipid metabolism', Proceedings of the Nutrition Society, 76 (3), pp. 361-368.
Antoni, R., Johnston, K., Collins, A. and Robertson, M. (2018) 'Intermittent v. continuous energy restriction: differential effects on postprandial glucose and lipid metabolism following matched weight loss in overweight/obese participants', British Journal of Nutrition, 119 (5), pp. 507-516.
Patterson, R., Laughlin, G., LaCroix, A., Hartman, S., Natarajan, L., Senger, C., Martínez, M., Villaseñor, A., Sears, D., Marinac, C. and Gallo, L. (2015) 'Intermittent Fasting and Human Metabolic Health', Journal of the Academy of Nutrition and Dietetics, 115 (8), pp. 1203-1212.
Rynders, C.,, Thomas, E., Zaman, A., Pan, Z., Catenacci, V. and Melanson, E. (2019) 'Effectiveness of Intermittent Fasting and Time-Restricted Feeding Compared to Continuous Energy Restriction for Weight Loss', Nutrients, 11 (10), pp. E2442.
Sainsbury, A., Wood, R., Seimon, R., Hills, A., King, N., Gibson, A. and Byrne, N. (2018) 'Rationale for novel intermittent dieting strategies to attenuate adaptive responses to energy restriction', Obesity Review, 1, pp.47-60.