Here’s What You Can Expect In The First Week Of Weight Loss (The Good And The Bad)

Let’s talk about what to expect in the first week of your weight loss journey!

We’ve measured up, we’ve set our goals, we prepped and devoured our meals and we have completed each of our scheduled workouts for the week. For all sense and purposes, we are riding high, ticking boxes, feel a-m-a-z-i-n-g and ready for weight loss. BUT, for so many of us, this feeling can so quickly turn on its head when we step onto the scales for our first weekly weigh in.

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Why is it that this ‘number’, this scale weight, holds so much ‘weight’ on how positive we feel?  Today’s little chat is taking us all back to the beginning. For those that are just starting out on their own weight loss journey, I want to talk about what to expect, the good and the not so good, for that very first week, and why, slow and steady wins the race!


What To Expect After 1 Week On Your Wellness Journey – The GOOD

 1) Large scale weight decrease-

This goes in both the GOOD and NOT SO GOOD- I need to clarify that when most people put a goal to ‘lose weight’ they actually mean they want to ‘lose fat weight’. The problem is that the weight we see on the scale includes our whole body:  bone, muscle, tissue, fat AND water. When we embark on a ‘weight loss diet’ often our intake of sodium (salt) and carbohydrate drops too. Both of these nutrients work in our body to retain fluid in the muscle. Carbohydrate by means of glycogen (our muscle fuel). By decreasing their intake whilst in a calorie deficit, our bodies drop this body water quickly. This results in one of our most considerable scale weight decreases for our whole journey on our first weigh in. I have put it in both sections, as it can be motivating, and we may feel better with less fluid bloating. However, it is also important to know that although there is a small amount of fat loss occurring at week 1 much of this first weeks ‘loss’ is water and our body will adjust and fluctuate in the coming weeks as it gets used to your new intake.

2) Improved Sleep-

With as little as one weeks increase in daily exercise and improvement in nutrition our bodies are already looking forward to a restful slumber. Ensuring positive sleep hygiene prior to bed will also assist this quickly gained positive outcome.

3) Cholesterol-

Exercise has been shown to increase ‘good cholesterol’ whilst changes in diet to include less saturated fat and fibre can decrease ‘bad’ cholesterol. These effects are noted within the first week of introducing these changes.

4) Blood Pressure-

Like Cholesterol a change in diet i.e  increasing fruit and vegetables and decreasing sodium rich foods as well as regular exercise can lead to noticeable Blood Pressure changes. These changes can be observed in as little as one week.

5) Regular toileting-

Exercise stimulates our smooth muscle (our bowels) and improved water intake and fibre intake along with overall improved nutrition assists our gut flora and gut mobility leading to a more regular toileting habit.

What To Expect After 1 Week On Your Wellness Journey – The NOT SO GOOD

 1) Large scale-weight decrease

I am including this point here too.  The negative to this large decrease is that the first week (or two) is often our largest ‘scale weight loss’ due to our body using up its glycogen stores and dropping fluid fast. Fat loss is still occurring weekly but your visibility of this is not yet evident and worse… is ‘blurred’ by those early week numbers. Stay consistent and the results will follow.

2) Muscle soreness-

Any new fitness routine can result in sore muscles also known as DOMS (delayed onset muscle soreness). The effects of muscle soreness do improve over time, however can be improved by ensuring a good warm up (to help blood and oxygen flow), cool down and appropriate nutrition, water and sleep to optimise recovery.

3) Hunger-

To lose weight we need to create a calorie deficit. By combining a balanced diet that is high in fibre, and adequate water intake each day we can reduce the frequency and intensity of those initial hunger pangs. Taking our journey a little slower by focusing on overall habits rather than ‘quick weight loss’ can also reduce hunger pangs.

4) Headaches-

These can happen for a couple of different reasons. A) Changes in our food intake, even positive changes, can result in some people getting transient headaches due to food intolerances. B) Calorie deficit can leave some with headaches triggered from a lower blood sugar level – regular small meals and eating soon after exercise can minimise these ones. C) dehydration from an increase in activity without meeting the changing fluid requirements.

5) Bowel issues-

Constipation or diarrhoea can result with any change of food intake. This can be a ‘volume’ of food in the gut issue, dehydration with increased requirements OR possibly an undiagnosed food intolerance.


In the absence of any medical cause, all of the above usually resolve on their own with slight correction over a few weeks (i.e. drinking more water, ensuring adequate rest etc.)

So there you have it!

After 1 week, it may not feel like it but each workout and meal choice is setting you up for positive results in the future – both physically and mentally. Remember that losing weight is only part of the journey. Creating healthy habits to keep it off as well as improving overall wellness is best done by choosing a journey that allows you to be consistent in the long term.

Amanda Turbill, APD, MNutr&Diet, BSc (Molecular Genetics)
A self confessed foodie, nutrition nut and fitness advocate. Amanda gets to live her passions daily as a Dietitian with 12WBT. Having been a high level gymnast until her late teens she still tumbles to this day and believes to maintain life balance it's important to find ways to incorporate 'play' to daily life . A Bachelor of Science (Molecular Genetics) and Masters in Nutrition & Dietetics she has over 20 years working across all clinical nutritional specialties with a particular interest in Nutrigenomics, food allergy and food intolerance. Amanda is a proud mum and is always keen to help other parents nourish, and stay active together with, their own families.

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