Is intermittent fasting good for weight loss?
Intermittent fasting can help with losing weight and reducing body fat IF:
1) Adequate protein is eaten
2) You engage in regular strength training (body weight counts too!)
3) You are in a calorie deficit
Adequate protein and regular strength training help reduce the loss of muscle mass during a calorie deficit and ensures that the majority of weight loss is due to fat loss.
Is it true you can feast on anything and still lose weight with intermittent fasting?
How does intermittent fasting work?
Instead of restricting what you can eat, intermittent fasting limits when you can eat.
Intermittent fasting has multiple variations. The most popular intermittent fasting regime is 5:2, where you “feast” for 5 days and “fast” for 2 days of the week.
On the feast days, you can eat as much as you.
The catch is that, on fast days you eat less than 500 calories.
There is also time-restricted feed where the eating window is limited to 6-8 hours. For example, a 6- hour eating window may look like, only eating from 8am to 2pm.
Most individuals eat within a 10-12 eating window, therefore, this often limits food intake by resulting in less opportunity to eat food.
Is intermittent fasting better than regular diets?
You might be surprised to know that intermittent fasting is just as effective as a regular diet.
Most diets are considered to follow a “continuous energy restriction” method. This is when calories are reduced by a certain amount every day, for example you may try to lose weight by eating 500 calories less per day.
In contrast, intermittent fasting limits the time in which you can eat, which results in an overall calorie deficit at the end of the week.
A recent systematic review and meta-analysis on intermittent fasting, has found that intermittent fasting results in a similar amount of weight loss as a diet where calories are reduced by the same amount every day.
In this review, participants had similar changes in weight loss, ranging from 4-8% of total body weight within 8-24 weeks. [1] The only significant benefit that intermittent fating may have over other methods is that it may help with reducing appetite.[2]
Is Intermittent Fasting safe and healthy for everyone?
Long story short, no.
There are many situations when intermittent fasting may do more harm than good.
Take caution and consult your doctor, dietitian and healthcare team if:
1. You have diabetes, especially if they are taking insulin or anti-diabetic medication. If you are intending to attempt intermittent fasting while on medication, you may need to adjust it to prevent hypoglycaemic episodes where your blood sugar levels drop too low.
2. You are pregnant or breastfeeding. During pregnancy and post-partum, a big focus is ensuring both you and your baby get enough energy, protein and micronutrients for healthy growth. Intermittent fasting may make it more difficult for you to get adequate nutrition. In addition, intermittent fasting can reduce breast milk supply and composition of breast milk.[3][4]
3. You have struggled with or are currently restricting and/or bingeing. Due to the nature of intermittent fasting, it can make it more difficult to develop a healthy relationship with food.
4. You have reflux. This might sound like an odd one but as someone who also experiences reflux, having 1-2 big meals within a narrow eating frame can exacerbate your reflux symptoms. Instead, small and frequent meals help with the management of gastroesophageal reflux disease (GERD).
Would you recommend intermittent fasting?
- There are situations when intermittent fasting is beneficial, for example, shift and late-night workers may prefer to fast during their work hours. This allows a regular eating daytime eating schedule to be mimicked and may result in better fat loss, weight management and sleep. There is research showing that eating late at night interferes with our circadian rhythm and sleep patterns.
- Also, some individuals naturally eat in a narrow window and prefer this intermittent fasting pattern.
- If you are considering trying intermittent fasting, remember that the fundamental healthy-eating principles still apply, and it is not a “free for all” on feast days.
How much weight can you lose with intermittent fasting?
How long do you have to intermittent fast for, until the weight to comes off?
· You will likely notice changes within the first 3-4 days with intermittent fasting, especially after a fast day. This is because less gut residue, reduced glycogen stores (from reduced carbohydrate content)
· On the other hand, you may notice large fluctuations in your weight if you weigh yourself daily due to these 2 factors. If you successfully follow the intermittent fasting guidelines, in addition to healthy eating principles, it is possible to notice meaningful changes to your body fat and weight within the first month.
Most individuals lose between 3-5 kg within 10 weeks of intermittent fasting or following a continuous energy restriction diet. [5]
What are the negative effects of intermittent fasting?
1. Hunger, fatigue, difficulty concentrating, lowered energy levels.
2. Social isolation. Not being able to eat out and participate in social occassions on “fast days” may result in some individuals distancing themselves from others because it’s “easier to stay on track.” This has harmful effects on mental wellbeing and with careful planning, social occassions should be included even if you are trying to fast.
3. Bingeing and feeling out of control.
4. May limit strength and muscle gain. Reducing your eating window may limit your muscle-building potential by reducing the opportunity to stimulate muscle synthesis.
Eating out on a diet is possible! Remember, your diet shouldn’t be making you miserable and should still allow you to celebrate the moments that are important to you.
What are the benefits to intermittent fasting?
1. Reduced appetite which may assist with better adherence
2. Equally effect to contious energy restriction to losing weight
3. May feel less restrictive or more suitable to lifestyle for somet inidviduals e.g. allows for more flexibility on social occassions
Do I need to take vitamins while fasting?
If you are eating a balanced diet and not avoiding any foods, vitamins and supplements are generally unnecessary. However, if you are unsure, it is best to consult a dietitian for a dull dietary assessment
If you’d like assistance with finding the right dietary pattern for your goals, lifestyle and preferences, and obtain a full dietary assessment to ensure your nutritional needs are being met, enquire about an initial consult today.
References
[1] Cioffi, I., Evangelista, A., Ponzo, V., Ciccone, G., Soldati, L., Santarpia, L., Contaldo, F., Pasanisi, F., Ghigo, E., & Bo, S. (2018). Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. Journal of translational medicine, 16(1), 371. https://doi.org/10.1186/s12967-018-1748-4
[2] Seimon RV, Roekenes JA, Zibellini J, Zhu B, Gibson AA, Hills AP, Wood RE, King NA, Byrne NM, Sainsbury A. Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Mol Cell Endocrinol. 2015 Dec 15;418 Pt 2:153-72. doi: 10.1016/j.mce.2015.09.014. Epub 2015 Sep 16. PMID: 26384657.
[3] A. M. Prentice, W. H. Lamb, Ann Prentice, W. A. Coward; The Effect of Water Abstention on Milk Synthesis in Lactating Women. Clin Sci (Lond) 1 March 1984; 66 (3): 291–298. doi: https://doi.org/10.1042/cs0660291
[4] Faris, Mo’ez Al-Islam E. and Al-Holy, Murad A. ‘Implications of Ramadan Intermittent Fasting on Maternal and Fetal Health and Nutritional Status: A Review’. 1 Jan. 2014 : 107 – 118.
[5] Seimon RV, Roekenes JA, Zibellini J, Zhu B, Gibson AA, Hills AP, Wood RE, King NA, Byrne NM, Sainsbury A. Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Mol Cell Endocrinol. 2015 Dec 15;418 Pt 2:153-72. doi: 10.1016/j.mce.2015.09.014. Epub 2015 Sep 16. PMID: 26384657.
