Intermittent Fasting For Weight Loss (Does It Work?)

Intermittent Fasting has been around for a while, but lately it has been getting a lot of attention.

  • Does it work?
  • Is it safe?
  • Should you try it out for yourself?

Here’s the deal:

A study published in the Journal of Translational Medicine (2016) found that practitioners of intermittent fasting for 8 weeks lost more body fat than those in the study control group.

The American Journal of Clinical Nutrition (2007) found that intermittent fasting helps prevent chronic conditions, like heart disease and Type 2 diabetes.

How Intermittent Fasting Works:

Intermittent Fasting (IF) is a lifestyle of eating that involves regular, short-term fasts.

One big meal is consumed per day with planned snack times to avoid overeating.

Benefits of fasting for short periods of time:

  • eat fewer calories
  • reset weight loss hormones
  • lower chance of decision fatigue
  • less time spent cooking
  • reduces cravings for sugar and salty snacks
  • inflammation and free radical reduction

Tips for Success:

  • Calorie intake must be reduced in order to lose weight.
  • Drinking water during fasting periods decreases hunger or cravings.

Up until recently:

Nutrition experts believed that 5-6 small meals per day were needed in order to maintain a healthy weight or to lose weight.

Short-term fasting may be a better way to increase fat burning!

Effects On The Body

Our bodies store fat as a way of storing energy that has been consumed (calories).

When we don’t eat, the body is then forced to make stored energy more accessible for use.

Fasting impacts metabolism by:

  1. Insulin: Insulin naturally increases when food is consumed. During fasting, insulin in the body decreases. Lower levels of insulin help to rev up fat burning.
  2. Human Growth Hormone (HGH): When fasting, levels of HGH may skyrocket as much as 5 times! This hormone helps with fat loss and muscle gain.
  3. Norepinephrine(noradrenaline): The nervous systems sends this to fat cells, causing them to break down body fat into free fatty acids that can then be used for energy.

So, now we have to ask…

Is Intermittent Fasting Safe?

Intermittent fasting has been proven safe except in these situations:

  1. Taking medication that affects blood sugar. Those using insulin or taking a drug like metformin, need to eat regularly. Going too long in between meals could cause blood sugar to drop, which could be hazardous to health.
  2. Addicted to carbs. Eating an abundance of carbs will cause trouble keeping blood sugars stable. Eating too many refined carbs will spike blood sugar and insulin levels, then cause a crash. This will cause extreme hunger and irritability during fasting periods.
  3. Have/had an eating disorder. Psychologically, this lifestyle could mimic restriction and binging phases found with eating disorders and could cause a flare up.
  4. Pregnant or trying to become pregnant. During this time, focus on eating healthy, nutritious foods and maintaining a healthy exercise regiment instead of trying to lose weight.
  5. On medication needing to be taken with food. Some medication needs to be taken with food to prevent upset stomach. Talk to your doctor that prescribed the medication to see if IF is a good fit.

Who Should Do Intermittent Fasting?

Intermittent fasting might be a good fit for you if you:

  1. Are frequently hungry. When using IF, hunger hormones are not triggered as often so hormones can balance out.
  2. Have self-control issues. Having a smaller feeding time naturally reduces calories consumed for most so having a cookie or two once in a while should not have a large impact on weight.
  3. Are Pre-diabetic. IF can increase insulin sensitivity, because going longer between meals lowers insulin released by the body.
  4. Hit a weight loss plateau. IF revs up metabolism when glucose is not readily available, so fat stores get burned instead.
  5. Have clearance from doctor. Only health care professionals can determine feasibility of any lifestyle change.

Does it Work For Weight Loss?

Many videos online show people that have tried IF for 1-2 weeks and haven’t really experienced any benefit so they stop.

A study on Type 2 diabetes prevention using IF found that body weight can be reduced by 3-8% over a period of 3-24 weeks, which can be considered to be significant weight loss.

The study suggests trying intermittent fasting for 3-24 weeks, not 1-2 weeks.

During this study, half a pound a week was lost with traditional intermittent fasting (16/8) but one and half pounds or more when using alternate day fasting methods (fasting for 24 hours).

Results For Fat Loss

The majority of those studied lost 4-7% waist circumference, indicating that significant stomach fat was lost.

Visibly losing belly (visceral) fat means fat was first lost around internal organs, which improves overall organ function!

Intermittent fasting is beneficial for:

  • weight loss
  • breaking food addiction
  • improving metabolic health
  • preventing chronic diseases
  • increasing brain function

Good for Building Muscle?

Bodybuilders consume protein every 3-5 hours for maximum muscle gain.

Protein synthesis must be spiked throughout the day and muscle burns calories faster than fat.

Caloric surpluses trigger muscle gain so intermittent fasting is only beneficial for those who:

  • are able to gain weight by eating fewer calories or
  • can consume more calories in a shorter time

Is Intermittent A Sustainable Lifestyle?

Practitioners of IF are most successful when treating this as a lifestyle rather than a diet by:

  • Minimizing carbs
  • Eating healthful fats such as olive oil, coconut oil, olives, eggs, butter, nuts, and avocados
  • Increasing water intake
  • Using IF for months rather than weeks

Psychologically, dieting results in less success long term than committing to lifestyle changes.

Can Intermittent Fasting Be Done Everyday?

Planning to fast on a consistent basis and prepping beforehand make it possible to fast everyday safely.

Action steps:

  • keep plenty of water available
  • plan work or travel around feeding times
  • get family/friends involved
  • pre-determine fasting frequency
  • have vitamin rich foods and snacks ready

What Can You Eat?

Stick to the basics for healthy eating in moderation while watching calories consumed:

  • Fruits
  • Vegetables
  • Whole grains
  • Lean protein
  • Nuts, beans, seeds
  • High fiber
  • Unprocessed foods
  • Fish
  • Potatoes
  • Probiotics
  • Eggs

When Should I Workout?

Working out during a feeding window gives immediate energy to burn through without feeling lightheaded or sluggish.

Doctors do not suggest working out on an empty stomach because this may cause feelings of weakness and could cause low blood sugar/glycogen levels.


The British Journal of Nutrition found that men burned 20% more fat when running before breakfast.

Intermittent Fasting on a Keto Diet:

A study in the International Journal of Obesity stated:

“Mattson has also researched the protective benefits of fasting to neurons. If you don’t eat for 10–16 hours, your body will go to its fat stores for energy, and fatty acids called ketones will be released into the bloodstream. This has been shown to protect memory and learning functionality, says Mattson, as well as slow disease processes in the brain.”

Human bodies reach ketosis by not eating any food at all or by limiting carb intake. Ketosis is a state where the body is actively breaking down fat into energy.

IF aids in depleting glucose reserves which speeds up the process of entering keto and burning fat.

Keto diet consists of:

  • low carb intake
  • moderate protein intake
  • very high fat intake

Ketosis deprives the body of glucose the same way fasting does. Using Keto and IF together reduces hunger and cravings while burning glucose and then fat reserves.

Can Intermittent Fasting Cause Weight Gain?

Yes, if eating the same or more calories than what is being burned.

Intermittent fasting is meant to create a calorie deficit and make the body want to consume fewer calories during the feeding window.

This is not a “magic pill” method where eating everything in sight will result in weight loss.

Which Fasting Method Is Best For Me?

  1. The 16/8 Method: Breakfast or dinner is skipped every day and eating is allowed during an 8-hour window. 12 noon to 8pm is the average feeding period.
  2. Eat-Stop-Eat: Doing one or two 24-hour fasts every week.
  3. The 5:2 Method: Eat 500-600 calories on 2 days of the week but eat normally the rest of the week.

The 16/8 Method is the most popular because of versatility and ease of use for beginners.

Alternate day fasting results in faster weight loss but is physically more difficult.

What’s the Maximum Safe Fasting Time?

This study found that fasting for up to 48 hours can boost your metabolism by 3.6-14%. And this study found that fasting for any longer than 48 hours can suppress your metabolism.

Research has shown that intermittent fasting contributes to healthy, long-term weight loss and keeps weight off by reducing the number of daily calories consumed.

Dee is a health conscious mom, and wife who loves to write when she isn't at the gym.
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