Intermittent fasting is a popular eating regime for weight loss. Let’s take a closer look at what the science says to determin if its something you can consider for healthy weight loss. By healthy weight loss, I am referring to a regime that allows you to stay healthy and active, through the weight loss process. Plus, it should allow you to keep the weight off after you have lost it.


The most popular form of intermittent fasting for weight loss is the 16:8-hour regime. For this, you fast for 16 hours and eat for 8 hours. During the 8-hour window, you are allowed to eat anything (1). For healthy weight loss, limit excessive intake of fat, saturated fat, sugar and calories. This implies no fries, chocolates, big portions of desserts or alcohol.


The general belief is that it works because:

1. You only have 8 hours to eat. With limited eating time, you are likely to eat less food and calories.

2. You have to follow a routine. Time limit contributes to a sense of routine and encourages a disciplined lifestyle which supports weight loss (1).

3. You have to be disciplined and committed.  You have to eat dinner by 6.30pm, to be able to eat breakfast at 10.30am. Also, as people begin to see weight loss results, they will be more likely to include exercise in the routine too, to expedite the weight loss process.


Researchers have determined that intermittent fasting is a healthy way to lose weight because it:

1. Is not physically or mentally harmful (in terms of mood) (1). Physically, your goal should be to consume a balanced diet. For a good balance include the following food in your diet daily:

-Whole grains – at least 3 servings
-Vegetables – at least 2 bowls
-Fruit – at least 2 servings
-Protein-rich food – 2 palm-sized portions of meat, fish or poultry OR 2 bowls of lentils, beans, peas
-Low or non-fat milk – 2 cups.

Also, limit excessive fat and saturated fat intake. With this diet, you probably won’t be nutritionally deprived. Visiting a dietitian may be a good idea, to ensure you don’t compromise your dietary intake. For additional nutritional insurance, you could also consider taking a multi-vitamin mineral supplement.

2.Contributes to some weight loss and is equal to a standard calorie restricting regimen when it comes to weight loss (1).

3. Helps you establish a daytime eating routine which leads to improved energy metabolism and body weight regulation. A daytime eating routine is important, as night time eating increases appetite-regulating hormone levels (leptin, ghrelin, xenin) and contributes to excessive calorie intake (1).

4. Lowers insulin levels & supports overall metabolic health. This may probably be due to the fact that it limits night-time eating, which contributes to reduced sleep duration and poor sleep quality, which in turn leads to insulin resistance and increased risk of obesity, diabetes, cardiovascular disease and cancer (1).

5. May improve gut microbiota by promoting growth of ‘lean microbes’ which limit energy absorption, expenditure and storage. Late night eating promotes growth of ‘obese microbes’ which contribute to an increase in energy absorption from the diet. It is also believed that these obese microbes increase risk of inflammation, which is a risk factor for many chronic diseases (1).

6.Reduces fat mass (2, 3), i.e., you lose more fat vs. muscle.

7. Lowers blood LDL or ‘bad’ cholesterol and triglyceride levels. This translates to lower risk of cardiovascular disease (2, 4)

Current research is based mainly on animal research. Researchers are trying to determine why time-restricted eating has a positive impact on weight loss and overall health. Research in humans needs to focus on length of fasting time, optimal fasting regime, and ideal calorie intake. Research also need to understand improvement in human health with long-term nightly fasting (1).


If the 16:8-hour intermittent fasting regime works for you, go ahead and adopt it for weight loss, as it is likely to help you lose weight and keep it off. In addition, it also helps you limit night-time eating and offers up other health benefits. The only caveat is, that if it lasts longer than a week, it would be best for you to meet with a registered dietitian, to evaluate your overall diet and nutrient intake. Vitamin or mineral supplements may be required, if dietary intake is inadequate. For nutrition insurance, consider vitamin and mineral supplements which provide at least 50% of the daily requirement for all key nutrients. If your nutrient and dietary intake is adequate, and weight loss is occurring for you, you feel healthy and energetic, you could even consider adopting intermittent fasting for life.


Yashna Harjani

Yashna Harjani

I provide strategic nutrition tips on the approach to health and wellness linked innovations, communications and external engagement.

This Post Has 2 Comments

  1. shweta yallatti

    I was following IF found dat my thyroid was gone for a toss.
    Does it affect thyroid??

    1. Yashna Harjani

      If you have thyroid issues, it is best for you to consultant a registered dietitian in your country. The dietitian will review your medical history, medication and dietary intake, and recommend a diet that best matches your needs.

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