Infograph: Drinking Water Before Meals Doubles Weight Loss
Easy Weight Loss

Drinking more water is probably the simplest, and easiest to stick to, strategy you'll find to help with weight loss. It's free (or at least cheap) and readily available in the UK - all you need to do to get started is turn on the tap! Here's the latest research

Does Drinking Water Help You Lose Weight?

The answer is yes. Evidence is mounting, and findings from the latest research show a very positive relationship between drinking water and weight loss.

Drinking water is probably the easiest, and cheapest, action you can take to help you lose weight.

So grab a glass and get sipping while we walk you through a range of recent research showing that the answer to the question is yes, drinking water helps to produce weight losses of moderate, but significant amounts.

How Does Water Help Weight Loss?

There are a number of theories out there amongst the scientists, some of which are solidly backed up by the research, others which are more hypothetical.

These seem to be the most likely explanations:

Feeling Fuller

Test meal studies have shown that drinking water prior to and during meals increases satiety and changes in feelings of satiety are associated with a lower overall calorie intake which, in turn, leads to weight loss. 

Increasing Metabolic Rate

Water drinking may provide thermogenic increases metabolic rate. A faster metabolism burns more calories.

Mobilising Fat Stores

Water is essential for metabolising stored fat into energy, so much so, that the body’s metabolism could be slowed down by even fairly mild levels of dehydration. The slower your metabolism, the harder it is to lose weight.

Drinking Less Calories

The more water you drink, the less need you have for drinks that contain calories. The fewer calories you consume, the more weight you'll lose.

Research on Water ‘Preloading’ Before Main Meals

These studies get people to drink half a litre of water before each of the three main meals in a day.

Published in the September 2015 issue of the journal Obesity, a randomized controlled trial was conducted with obese adults recruited from general practices in Birmingham. 

Participants were split into two groups:

  1. Participants were instructed to drink 500 ml of water 30 min before their main meals, 3 times a day
  2. Participants were asked to imagine their stomach was full before meals.

Both groups were given a face-to-face weight management consultation at the start and a follow-up telephone consultation two weeks later.

After 12 weeks, the people who were instructed to drink the water lost twice as much weight as the full stomach imaginers, and 5 times as many of them lost 5% or more of their body weight.

Another water preloading study, published in the Journal of Clinical and Diagnostic Research in 2013, carried out a study on overweight young women. This research showed similar results in terms of weight loss though the researchers believe this is mainly due to the thermogenic effect of drinking water leading to increased metabolic rate and, therefore, more calories burned.

Does it Have to be Water?

Not necessarily. Substituting no calorie drinks of any kind for drinks containing calories, results in a lower calorie intake which leads to weight loss.

A randomized clinical trial published in The American Journal of Clinical Nutrition in 2012, showed that participants who replaced drinks containing calories for either water or diet drinks lost more weight than those who tried to lose weight by making healthier food choices. 

Participants in the drink replacement group were also twice as likely to achieve a weight loss of 5%.

A later study published in Obesity in 2014 suggests that diet drinks may be even better than water for people following a weight loss regime.

In this study, participants followed the same behavioural change plan for weight loss. 

One group was required to drink 700ml of water during a day, the other group drank 700ml of no calorie diet drinks. 

In the Water group, 43% of participants lost more than 5% of their body weight, while 64.3% of participants in the diet drink group lost more than 5%. The diet drink group also reported lower hunger scores.

WLR Says

The evidence is that drinking water, and possibly other zero calorie drinks, can help you lose more weight than if you were relying on healthy eating or calorie restriction alone.

The amounts of weight lost in these studies are all relatively modest, but still significant. A weight loss of just 5% can have a major impact on long-term health.

Drinking more water is probably the simplest, and easiest to stick to, strategy you’ll find to help with weight loss. It’s free (or at least cheap) and readily available in the UK – all you need to do to get started is turn on the tap!  

For people who are trying to lose weight we recommend:

  • Drinking half a litre of cold water, half an hour before each main meal of the day
  • Drinking water or other calorie free drinks during meals
  • Replacing drinks containing sugar with sugar free drinks
  • Drinking enough water or zero calorie drinks to keep well hydrated

How do you know if you're well hydrated? Your wee should be the colour of pale straw.

Successful Losers Views

Here's some water drinking tips from WLR members who have lost weight successfully:

"Drink lots of water, at least 2 litres a day - it's important to keep your body properly hydrated if you expect it to work properly. That way it will cope with the other changes you are making so much better." WLR member Stella (lost 5 stone 8lbs)

"Drink lots of water – this initially is a pain as you run to the loo every 20 mins! However think of all that extra exercise you are getting by getting up out of your seat to go! I find my skin is much nicer now I drink lots of water. I don’t always manage 2L a day like I should, but I have experimented for a 1 week period by drinking 2L every single day – and I lost more than 3lbs that week. I know if I want a good loss on a particular week, I have to drink loads of water!" WLR member Michelle (lost 1 stone 9lbs)

"Water is your friend – I drink 3-4 litres (yes three to four litres!) a day. Sometimes I put a bit of lemon squash in a 750ml bottle of water. Taste great and is still 99% water." WLR Member Gareth (lost 6 stone 11lbs)

Drinking Water to Lose Weight?

WLR can help you develop the good for weight loss water habit by enabling you to monitor what you're drinking. It also helps you change your eating habits Try it Free for 24 hours.

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