How to Lose Weight Fast

It’s 99% in the kitchen !


Happy Thanksgiving!

This marks the beginning of the holiday season. For many, it also means packing more weight. Which leads to the question: How do you lose weight?

I am totally against fad diets or short-term solutions. It is better to reach a healthy weight through sustainable habits, such as good meal planning, even if it takes a year. Yet I see valid cases for losing weight quickly:

  • You are required to pass soon a physical exam, such as police, marine corps, army tests. The physical exam has maximum weight requirement, as well as running times you can only achieve through lower weight.
  • You are competing in a boxing or martial arts tournament and target a lower weight class
  • You have pre-diabetes or Type 2 diabetes and need urgently to reach a healthy weight to alleviate painful symptoms
  • You over-indulged recently, gained a lot of weight, and it would be ridiculous to buy new clothes
  • You are applying for a job where weight is an issue. e.g. security guard, model, fireman

In these cases, I have found a way to lose 2 to 8kgs in a couple of weeks, before returning to a maintenance phase. Here is what works for me:

Ketogenic Diet

Weight loss is 99% in the kitchen. Exercise can help but won’t reverse poor diet. It is therefore key to choose the best diet.

A ketogenic diet is a high-fat and low-carbohydrate diet. Proportions target 60-75% of calories from fat, 15-30% from protein, and 5-10% from carbs. Originally for treatment of epileptic children, it has been found beneficial for treatment of Type 2 diabetes, cardiovascular risk parameters, weight reduction and also for endurance athletes, as you will see later. Clinical trials demonstrate:

  • Positive influence on neurotransmitter activity in epileptic children
  • Reduction of blood insulin
  • Reversal of hepatic insulin resistance
  • Reduction of appetite
  • Increased LDL particles leading to improved blood cholesterol levels (quantity and quality)
  • Reduction of lipogenesis
  • Increased lipolysis
  • Increased metabolic cost of gluconeogenesis and thermic effect of proteins, leading to weight loss

This sounds wonderful. Putting it in practise is more challenging. You will have to track all food intake. 5% of daily calories from carbs means you will have to cut flour, rice, pasta, pizza and many sweet fruits. Even most dairy will need to be cut. Of course, sugar and honey cannot be part of the diet. They all need to be substituted for healthy fats: olive oil, coconut oil, avocado, fatty fish (e.g. salmon, sardines), nuts such as almonds or walnuts, or full-fat cheese.

Headaches, uneasiness and fatigue usually occur when adopting a keto diet. Keto-adaptation occurs over several weeks when the body switches from using carbohydrates to fat for energy. The liver start producing ketones—small lipid-derived molecules produced in the liver—and fatty acids to be used as a primary energy sources instead of glucose. After keto-adaptation though, you will find renewed energy and better focus.


It is possible to lose a drastic amount of weight on this diet. As your body uses reserves of carb from your excesses, it will also shed 3g of water from each 1g of carb lost. If you are not overweight, you can even notice facial changes, such as sunken eyes or less face bloating.

Doesn’t the body need carbs? It is widely believed that carbs are our #1 source of energy. In reality, there is no dietary requirement for carbohydrates. Our body is entirely capable of producing glucose through gluconeogenesis. In fact, major systems like the brain actually prefer ketones over glucose as fuel. Being fat-adapted also means quasi-unlimited reserves of energy for endurance sports – compared to other athletes who only have 2,000 calories of carbs at their disposal.

After reaching your target weight, I highly recommend to switch to a more reasonable Low Carb High Fat (LCHF) diet. It is more flexible and you will be at least able to eat socially. More importantly, I find LCHF can be easily sustained over many months and years. I have been following LCHF and love it. As a matter of fact, triathlete champion Dave Scott follows this diet and is a 6-time world champion!

Make Sleep a priority

If you are not sleep enough hours, find a way to sleep more. If your sleep is light and you do not spend time in deep sleep, research how you can increase your sleep quality.

Simply, poor sleep correlates with weight gain. See Study (1) and (2). This means that even if you fix your diet and exercise more, your hard efforts won’t mean anything until you sleep well.

I find myself that if I miss a couple of hours of sleep, I will see consequences on the scale. Don’t go out late, watch out caffeine, stay away from bright blue lights and noise pollution. Don’t let anything go between you and precious sleep hours !

Reducing Salt Intake

Salt contributes to water retention. Like the keto diet, this means changing food intake: no more fast food, no more processed food or eating out. The easiest way is to do groceries and cook everything — without salt.

Cutting salt for a few weeks will help shed face bloating and lower blood pressure. It makes sense especially after Thanksgiving and the holidays season where you’ve eaten a lot of salty food and simple carbs.

Caution: In the long term, cutting salt is not healthy. A diet without salt can result in hypothyroidism. After you have reached your targeted goal, I recommend adding moderate quantities of salt in your diet.

Getting Rid of More Weight

The next steps depend wether there are physical tests as well as weight test.

I find you can easily lose a few kgs by running long distances. I typically lose 2kgs by running 20km. You can exercise from week 1 with hard runs then taper 3 to 5 days before the final test. Hard and fast runs will increase your basal metabolic rate and will allow you to burn more calories every day.

If you do not exercise, an alternative is a sauna sessions. Like running, lost weight is mostly water. After weight is measured, you can drink and hydrate again.

Tracking Weight Loss

Like exercise, losing weight is an effort that requires consistent effort and mental toughness. It is easy to cheat. To keep losing weight, I find what works is by actively monitoring your weight.

I use a Withings Body Cardio Scale. I weigh myself every morning and it sends the data to various apps and platforms. You can clearly link weight increase or weight loss to what you have done recently: past exercise, a big lunch or maybe a meal you skipped.

The Withings scale works for me. I used to have the FitBit Aria scale. They are the leading products in this category, but I found both of them to be inaccurate and expensive for what they offer, especially in terms of body fat percentage. Pick whatever is the cheapest on Amazon or at your local store, and measure your weight at the same time everyday.

Maintenance Diet

Within the scenarios listed above (army tests, competition etc.), you can lose quickly 2 to 8 kgs in a few weeks. To prevent a rebound, it is important to review the diet at the end. You can consult a registered nutritionist to make sure you are getting an optimal diet. You can also look into meal planning, outlined previously.

Happy Thanksgiving and happy weight loss !


  1. Sanjay R. Patel, Atul Malhotra, David P. White, Daniel J. Gottlieband Frank B. Hu Association between Reduced Sleep and Weight Gain in Women. American Jnl of Epidemiology Volume 164, Issue 10Pp. 947-954
  2. Chaput JP; Després JP; Bouchard C; Tremblay A. The asso- ciation between sleep duration and weight gain in adults: a 6-year pro- spective study from the Quebec Family Study. SLEEP 2008;31(4):517- 523.

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