Intermittent fasting (IF) is one of the biggest buzzwords in the health and wellness space today. It started gaining momentum around the beginning of 2017 and it is being driven to further heights by the highly popular keto movement. Just look at the google search trend graph below.
Put simply, intermittent fasting is not a diet. It is a set of easy to follow eating patterns that a majority of people can follow. The eating schedules involve individuals going for extended time periods with little or no energy intake, with in-between periods of normal food intake.
It is also important to distinguish between intermittent fasting and time restricted feeding (TRF). Intermittent fasting generally involves longer fasts that goes beyond 24 hours while time restricted eating is considered to be a form of fasting where you restrict your eating schedule to a certain window during the day. Keto, paleo and low carb diets works really well when combined with TRF.
Different Forms of Intermittent Fasting
IF can be classified into 3 big categories:
The 16/8 Method - You fast for 16 hours each day and eat during the other eight. This time-restricted feeding schedule is the most opted for method and goes by the name of Leangains protocol.
The 5:2 Diet: Also called as the FAST diet, you fast for 2 days in a row per week and restrict calorie intake to 500-600 calories on those two days. You can also combine this with time restricted eating for better results.
Eat-Stop-Eat: You undergo a 24-hour fast, once or twice a week. This is a lot harder to do as you are only consuming water during the fasting period.
Overall, intermittent fasting is very flexible, and you can combine elements for all 3 methods above to create your own custom eating schedule.
The Core Idea Behind IF - Ketosis
The core idea of intermittent fasting is to send your body into a state called ketosis and this is the reason IF works really well if you’re already on a keto-diet which is low on carbs. Ketosis is the state your body goes into when your body runs out of glucose to burn and starts burning fatty acids for fuel. What happens when your body gets used to a routine and expects carbs to burn (via the food you consume) at predictable intervals? You body will never enter into a state of ketosis and will continue converting carbs into glucose instead of fat. Intermittent fasting is meant as a way for your body to break out of this virtuous cycle by sending it into ketosis - a state where you body will run out of its glucose stores and starts burning fatty acids for energy.
Intermittent Fasting And Its Health Benefits
There have been numerous studies conducted on intermittent fasting. Few studies over the last couple of years have shown that IF or circadian rhythm fasting does help with weight loss, but all the evidence suggests that timing of the fast is key. A lot of factors goes into weight loss - your genetic predispositions, your behaviour, diet, environment, exercise and so much more. So it’s hard to definitively say that intermittent fasting alone is the means to an end when it comes to losing weight. Other studies show that there are no significant differences in weights of those on intermittent fasting vs those who aren’t. The group practicing IF however saw improved insulin sensitivity, β cell responsiveness (β cell produces and releases insulin & amylin) , blood pressure, oxidative stress, and appetite, showing that the benefits of IF goes beyond weight loss.
Autophagy is a natural process that occurs in your cells. The process essentially gets rid of all the junk that accumulates within your cell - discarding damaged mitochondria and recycling proteins. Fasting induces autophagy by starving cells.
A malfunctioning autophagy process is thought to contribute to neurodegenerative disorders like Parkinson’s and Alzheimer’s, because of certain proteins accumulating in cells. The process also clears pathogens and ensures that your mitochondrial function is optimal. Read more about the study on how it impacts neuronal cells here.
Cells over time sees a declining ability to process energy which in turn can lead to ageing and age related diseases. Research is now showing that caloric restriction combined with exercise can have a profound effect on health. It can stave off or slow down mental and physical degeneration associated with ageing, specifically by stopping the age-related deterioration of neuromuscular junctions. Other research studies are now showing how fasting promotes the plasticity of mitochondria networks by maintaining their youthful state. Time restricted feeding with fasting periods greater than 12 hours might also prove to be an effective treatment strategy for several chronic diseases.
Intermittent Fasting Is Not For Everyone
The Genetic Angle
However, there are some cases where you need to be wary. Mutations in the A/CADS and A/CADM genes cause what are known as inborn errors of metabolism. If you have this condition then you become prone to hypoglycemia and fasting becomes risky. You can read more about it here. For others though, it may well be a way to increase your lifespan.
If you already suffer from diabetes, have eating disorders, or are pregnant or breastfeeding, you probably shouldn’t attempt IF without supervision from a physician. Advanced stage diabetes cases are particularly at risk of hypoglycemia.
Tips For Following Intermittent Fasting
Start with a simple form of intermittent fasting - Consider starting with longer windows of 10 hour periods and gradually shortening it. Avoiding eating or snacking at night time and consider fruits with low glycemic indexes especially for breakfast. You can use Gini’s lens to figure out which fruits are the best for you.
Figure out your genetic predispositions
You can better tailor your diet this way. The 3 big ones are:
Satiety: Appetite stimulating hormone Ghrelin dictates how full you feel after a meal. Some people have an elevated risk and feel ‘hangry’ all the time and need to be aware of this risk to ensure that they don't binge eat.
Resting Metabolism: Your basal metabolic rate is how many calories you burn when you body is at rest. If you have a lower basal metabolic rate you need to consume fewer calories.
Saturated fat risk: One of the pitfalls of going on a diet like keto is the risk of having too much of saturated fats. Depending upon your genes, this can increase your risk of certain diseases and also lead to weight gain.
Meal timing: Meal timing is also dependent upon your genetics which influences your melatonin levels. Especially if you are prediabetic or suffer from diabetes, have an elevated genetic risk and also practice time restricted eating, you need to ensure that you eat dinner early and not have breakfast right away after waking up.