Can You Lose Weight While Not Eating for a Week?
This is commonly a trending search term on Google Australia.
The short answer is yes. Weight-loss, at the end of the day, is about being in a calorie deficit, I mean there are some complexities around where you get those calories from as I’ve discussed previously but you still have to create a particular set of circumstances for weight loss to occur and a calorie deficit is one.
I’ve discussed strategies in previous blogs and books on how to reduce overeating, curb cravings and limit the total amount of calories consumed over the day for someone wishing to lose weight. Running parallel to my strategies and recommendations is always health. Health is achieved by ensuring all your physiological/biological/neurological needs are met – via good quality nutrition.
Now, to not eat for a week would be side-stepping my last point. Depleting your physiology of the nutrients, vitamins and minerals for an extended period of time is potentially harmful and there are some much safer and less unpleasant methods to use. Fasting for 7 days is not recommended for someone unaccustomed to fasting or for someone not metabolically flexible (ability to burn fat efficiently). For a habitual ‘sugar-burner’ (someone on a high carb diet) to embark on a fast of any duration, let alone 7 days, would be very uncomfortable, to say the least.
Being metabolically flexible would probably lessen the uncomfortable nature of fasting and allow for sufficient flow of metabolised fat available for energy. That being said it would not be the time for exercising beyond ‘light’ exercise and definitely not any high-intensity training.
So what happens over the course of the seven days?
As a ‘sugar burner,’ you will have depleted glycogen stores in your liver after the first 1-2 days depending on activity.
The body will still need to operate and function normally despite the lack of dietary calories. For homeostasis to be maintained the body begins to liberate fat from adipose sites (fat cells) which then get metabolised in the liver and converted to ketones. The ketones then become available to all cells within the body. Any physiology process that requires glucose metabolism can occur as a consequence of protein or glycerol being broken down and converted to glucose.
Our body is incredibly robust and adaptive and can operate remarkably well on little or no calories. This is an evolutionary adaptation, periods of food scarcity have been an ever-present reality throughout our history.
Your body will soon recognise the scarcity of food and elicit some physiological processes such as an elevation of your sympathetic nervous system – enabling you to be extra vigilant and alert – perfect for gathering and catching food….your biology isn’t aware that you are in a deliberate 7 day fast it just fears the worse and kicks you into survival mode.
Autophagy or cell cleansing is up-regulated in a fasted state, particular one beyond 24 hours. However, in the ‘perceived’ survival state the body will also preserve any energy it can by partitioning any process that might be utilising energy, and example might be to slow metabolism for energy conservation.
Losing weight via a 7 day fast will occur but it’s a significant commitment and one I personally wouldn’t accept whilst adhering to a typical Western diet. I would want to have some ducks lined-up before taking the plunge which would include becoming fat-adapted and spending a considerable amount of time on high fat, low carb protocol as well as fasting for sequentially longer and longer periods of time.
Losing weight can be the bane of someone’s existence and can be intricate and complex but there are some fundamental principles that apply to all of us – the intricacies and complexities are primarily the psychological barriers, self-sabotage and proclivities to certain behaviours around food – but it’s all workable. This is what I do…
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