What is Intermittent Fasting?
Everyone’s familiar with intermittent fasting (IF) by now, but as a reminder, it’s a form of dieting in which you alternate eating days with fasting days, less about what you eat than when. There are many forms of intermittent fasting, but most involve a 12- to 48-hour fast followed by regular chewing. You might eat as you usually do most days of the week, yet eat for only eight hours and fast for the other 16 [1].
This eating pattern is a popular diet strategy, and interventions have demonstrated that it is an efficient approach to reducing weight, fasting insulin levels, and blood glucose. Furthermore, it increases the antitumor activity of drugs and improves neurological diseases (e.g., memory deficit) to aim for improved metabolism and prolonged life [2].
IF constitutes a diet or way of eating to reduce body weight in calorie-restricted individuals. Although some risks can arise from this way of eating, IF may ultimately be of value to diabetes patients as well [3]. The three most thoroughly investigated forms of IF are alternate-day fasting, time-restricted feeding, and the 5:2 diet [4].
What is the Purpose of Intermittent Fasting?
IF, a pattern of modified dieting in which eating is limited for defined periods followed by normal eating patterns, benefits the consumer in many ways because the advantages afforded by this eating style transcend several domains of health and wellness.
One of the main aims of IF is weight loss. On a molecular and cellular level, IF leads to a negative energy balance when the body is fasted and uses stored fat as an energy source [2, 5]. It successfully reduces weight, especially in the context of alternate-day fasting. Body weight is lowered by 3-7% after 3 to 12 weeks [5].
IF also improves metabolic health. Reducing fasting insulin and blood glucose represents a potential therapeutic intervention for various metabolic disorders, including diabetes, hypertension, or obesity, all treated with insulin and lightly insulin-sensitising medicines [2, 6]. This metabolic switch from glucose- to fatty acid-derived ketones is also a mechanism for preserving the mass- or function-dependent effects of fasting on skeletal muscle that might, in turn, improve body composition [7].
The second is another aspect of cellular health, perhaps of longevity: IF activates many biological pathways to bring on autophagy, which causes cell renewal at the individual cellular level while preventing cancer cells from forming and spreading and staving off cellular senescence [2]. In addition, IF has anti-inflammatory effects and is good for one’s gut microbiome [8].
Lastly, IF is used to enhance the effectiveness of certain treatments. For instance, it can increase the antitumor activity of medicines and improve neurological diseases, such as memory deficit [2].
What is the Influence of Coffee on Diet?
As an everyday staple beverage, coffee is a popular choice among people around the world. Its effects on diet and health have long been interesting, but its dietary impact is not always clear-cut.
Since coffee is rich in bioactive compounds – including caffeine, trigonelline and phenolics (the same polyphenols known to be health-promoting in other plant-based foods) – drinking coffee can be beneficial for overall health, reducing the risk of type 2 diabetes and neurodegenerative diseases, and protecting against certain types of cancer [9].
Regarding metabolic health, coffee increased antioxidant and anti-inflammatory responses but didn’t necessarily improve glucose homeostasis under an obesity model concerning fat-rich diets. Coffee consumption raises insulin secretion and stimulates muscle-based glycogen synthesis [10].
It is less clear how coffee impacts appetite and food intake. When consumed 0.5-4 hours before a meal, coffee consistently suppresses acute energy intake, while coffee intake 3-4.5 hours before a meal has no effect on food and macronutrient intake [11].
In fact, changes in coffee drinking seem to be associated with changes in foods. An increase in coffee intake during a trial was significantly associated with an increase in chocolate, sweets, cakes, sweet biscuits, pastries, and jams [12].
Can You Drink Coffee During Intermittent Fasting?
People who try this experience wonder whether it is okay to drink coffee while doing intermittent fasting. You can do it, but this answer is not straightforward either. It depends on several factors, such as how you are fasting and the type of coffee you drink.
And that means coffee, especially black coffee, is largely permissible to be ingested within your fasting window. That’s because black coffee is almost calorie-free and virtually devoid of protein, carbohydrates and fats that could perturb your fast [13].
However, your fast will slip if you add milk, cream, sugar, or sweeteners to your coffee, as these add calories and nutrients that may cause your metabolism to stir. So, if you drink coffee during your fast, you better make it black [13].
That includes some evidence that coffee is also good for metabolic health. In one study, coffee consumption was linked to lower odds of reduced risk of metabolic syndrome—a cluster of conditions, such as high blood pressure and high blood glucose, that increase the risk of heart disease, stroke, and type 2 diabetes [14]. In another study, coffee consumption was associated with a modest and consistent decrease in postload glucose, which could reduce the risk of diabetes [15].
On the other hand, coffee is a diuretic—it increases urine production and theoretically can even lead to dehydration, an issue if you’re fasting. Staying hydrated is essential [13].
In conclusion, while drinking black coffee during intermittent fasting is generally acceptable, it is important to pay attention to how your body responds and adjust your coffee consumption accordingly.