Decoding Diet: Why Intermittent Fasting Works for Some People And Not Others

Intermittent fasting is a metabolic method used to change the way the body utilises fat instead of glucose. It is based on the simple idea of limiting the eating time. While some people have reported quick weight loss and mental clarity, others have reported exhaustion and lack of progress. It is not just a matter of having the willpower; there is a calculation involved.

We spoke to Twincy Ann Sunil, Clinical dietitian and nutritionist, Apollo Spectra Hospital, Bengaluru, who explained why intermittent fasting works for some people and not for others.

Why Results Differ Among Individuals

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The science of fasting is consistent, but human biology is dynamic. Several key factors determine why the same fasting window produces different outcomes:

Differences in Metabolism

"The metabolism rate defines the rate at which the body can convert the food eaten into energy. Therefore, people with high metabolic rates have the ability to switch from the metabolism of sugar to the metabolism of fat when fasting," explained Sunil. However, people with slower metabolism rates and those with insulin resistance will not be able to make this switch, thus experiencing hunger instead of losing weight.

Hormonal Variations

hormones
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The hormones involved include insulin, cortisol, and ghrelin, which regulate hunger levels and fat storage. While intermittent fasting can improve the body's sensitivity to insulin, it may also put the body under stress. "For some individuals, especially women and those under high levels of stress, the body may respond to fasting by increasing the production of cortisol, commonly known as the stress hormone. Elevated cortisol levels can trigger a "famine response," causing the body to store more fat," said Sunil.

Lifestyle and Activity Levels

A person's daily routine will define the sustainability of a fasting regimen. For instance, a controlled office environment can make fasting during breakfast hours easy. Conversely, physically demanding activities or high-intensity training regimens can cause performance failures because nutrients will not be taken at optimal times.

Diet Quality During Eating Windows

"Fasting does not give anyone a free pass to consume as many calories as they want. Fasting with high levels of sugars and carbohydrates will cause insulin levels to skyrocket. In order to be successful with fasting, nutrient-dense foods must be eaten," warned Sunil.

What Can Be Done to Improve Results

In order to get results, the approach should be personalised rather than applying a universal timer. Some small changes can make a big difference in the way the body responds, such as:

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  • Choose a Realistic Pattern: It is recommended that one start with a 12:12 or 14:10 fasting pattern. This means that one can fast for 12 hours and eat during a 12-hour window, or fast for 14 hours and eat during a 10-hour window. This will give the body and hunger hormones a chance to adjust before moving on to a 16:8 pattern, which consists of 16 hours of fasting and an 8-hour eating window.
  • Prioritise Protein: Meals should be high in protein and healthy fats to protect muscle mass and increase fullness.
  • Maintain Hydration: Drinking plenty of water and utilising electrolytes can prevent "fasting headaches" and fatigue.
  • Prioritise Sleep: It is important to get enough sleep to reduce the levels of cortisol. This will help the body to easily access the fat reserves during the fasting period.

Bottomline

Sunil concluded, "Intermittent fasting is a useful tool, and it is not meant for everyone. The outcome of intermittent fasting is determined by one's unique biological composition, stress levels, and diet. The flexible approach to intermittent fasting is more sustainable and provides better results than forcing one's body into a schedule that does not suit its unique requirements."

Disclaimer: The information provided in this article is for general informational and educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or a qualified healthcare provider with any questions you may have regarding a medical condition.