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Red and Green (the point?)


I've been looking around at various diet plans but one thing that has intrigued me about SW is the Red Day / Green Day thing.

Fact is (as your faq states) that calories in has to be less than calories out for someone to lose weight.

So what's the benefit of having a protein heavy day one day and carb another? Other than to make meal times less interesting?

Is there any scientific evidenec to back up that this is beneficial?
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Silver Member
S: 11st7lb C: 10st0lb G: 10st0lb BMI: 23.3 Loss: 1st7lb(13.04%)
Hi Glenn,

Remember that SW offer the Extra Easy plan too - that should stop meal times being less interesting!

One of the general principles (but not the only one) of SW is to encourage you to eat lots of filling foods like fruit, veg, carbs (but not bread) and meat as you should feel fuller for longer, and be less likely to snack on highly calorific food afterwards or instead of meals.

Not that I've tried for quite a while, but I'm pretty sure if I worked out my calorie intake on SW at the moment, I'd still be eating a lot less calories than I did before I started - it's amazing how much veg you'd have to eat before you got close to the calories of a Mars bar!
S: 11st3.0lb C: 11st7.0lb G: 9st7.0lb BMI: 27.6 Loss: -0st4lb(-2.55%)
Yes, calories in vs calories out is the basis of weight loss, of course, but in reality it's a lot more complicated than that. There are all sorts of ways of reducing your calorie intake, and all diets do that in some form or another. SW's way is with Original (red), Green and Extra Easy days.

In the beginning, SW was just the Original plan, which was a low carb/high protein/low calorie diet. Then the powers that be introduced the green plan, which works for vegetarians whilst keeping the low calorie and 'healthy extra' elements of the original plan.

At the beginning of this year, Extra Easy was introduced, which combines carbs and protein but still retains the low calorie basis.

For me, being able to switch between all the plans allows me to eat a hugely varied diet. It stops me getting bored and giving up, it gives me flexibility to eat 'normally' including being able to eat out and not feel panicked!

Often in weight loss journeys, people hit a plateau. Having the option to shake things up a bit with the variety that different days offers can give people a way out of stuck phases.

I can't say whether there is any scientific evidence about swapping the days - perhaps you need to write to SW and ask them about it. I am sure they must have done some research over the years!

All I can say is that SW offers a really flexible dieting 'structure' that allows members to stick with weight loss regime. And it works. That's evidence enough for me!

Are you thinking of joining a slimming club?


Silver Member
S: 19st1lb C: 8st11lb G: 9st10lb BMI: 21.8 Loss: 10st4lb(53.93%)

Fact is (as your faq states) that calories in has to be less than calories out for someone to lose weight.

So what's the benefit of having a protein heavy day one day and carb another?
As far as I'm aware, there used to only be one SW plan, which is what we now know as 'Red Days'. This was based on having protein as Free Food as it was thought to have a good satiety level, and allowing small amounts of carbs.

'Green Days' were introduced in the late 80s as a way of allowing vegetarians to follow the plan, I think. In this case, carbs were used as the Free Foods and small amounts of protein included.

The 'science' behind this is based on the volumetrics system AFAIK, which has to do with this thing called satiety - how filling a food is for its calorie value. Ie, a plate of pasta might have the same calories as a 100g bar of chocolate, but it will fill you up a lot more and hence you won't want to eat anything else for a while. The chocolate is not going to stop you feeling hungry.

As you say, it all comes down to calories in versus calories out, and this is where satiety is very important. When I first started SW, I added up the calorie total of my day's food on several occasions and was amazed to find it coming out at under 1500 calories. I felt absolutely full and would not have believed I'd consumed less than 1500 with what I'd had to eat.

Personally I think the psychological aspect of SW is hugely important. It's been shown over and over again that if you tell someone 'you can't eat that', they immediately want to eat loads of it. The reverse seems to be true as well: if you say to someone 'you can eat as much of that as you like - have as much as you need to fill you up', they tend to stop once they're full. They don't have that compulsive need to eat as much of it as possible.
S: 14st13lb C: 14st13lb G: 10st0lb BMI: 38.2 Loss: 0st0lb(0%)
I'm not going to lie, i dont have the first clue (bar the obvious) how sw scientifically works..

all i know is, it does. I'm proof :)

Somtimes theres just no point questioning a good thing! x


its a long road
S: 22st10lb C: 20st6lb G: 16st0lb BMI: 47.6 Loss: 2st4lb(10.06%)
well heres a fact for you my dear ive been following the plan for 13 weeks now and ive lost 1 stone 12 pounds

and im eating loads and loads

so dont knock it cause it sounds crazy lol it works

many many many years ago it was a fact that the earth was flat too ;)
S: 20st0lb C: 19st1lb G: 11st7lb BMI: 41.8 Loss: 0st13lb(4.64%)
Hi Glenn

I previously lost quite a bit of weight on SW but due to family bereavement and feeling sorry for myself I went a bit off track but now am back.

This diet really does work hence my coming back to it. For me, I tend to mostly have green days due to being a Type 2 diabetic. Although I tend to have mostly carbs - these are the healthy carbs or as, in the case of bread, pulses, rices, etc. the "refined carbohydrates".

Refined carbs (wholemeal bread, brown rice, etc) are better for me as they break down slower, and therefore my body is able to break it down better with regards to insulin. As they break down slower, you feel full for longer and tend to eat less!

With this diet I can have the best of both worlds as I use my HExB to cover protein should I feel I want likes of a chicken curry, etc.

At the end of the day, the only proof we need is results, and believe me, this diet does provide them!

S: 16st6lb C: 9st6lb G: 9st6lb BMI: 24.1 Loss: 7st0lb(42.61%)
All diets restrict calorie intake. Slimming World do this by restricting the types of foods that you can eat on any particular day but they tell you that you can eat as much as you like of the foods that you ARE allowed.
Other diets let you eat any food as long as you count in terms of calories/points.


Slow but sure....
S: 22st0lb C: 19st7lb G: 10st0lb BMI: 55.1 Loss: 2st7lb(11.36%)
There is a old diet regime (1930/40's) called 'The Hay Diet', and that diet was that you did not mix protein's and carb's together in any one meal, and people who followed this diet lost weight.

SW may (I say 'may' in loose terms) have based the diet on this idea - but whether they did or not, IT WORKS, and that is all that matter's to us.

Try the diet yourself and see......


Is a crunchy mama!
S: 13st13lb G: 9st9lb
I think the reason why Slimming World separates the two food groups into protein heavy and carbohydrate heavy days is simply a clever way to restrict our overall daily calorie intake and to ensure that we are consuming fibre rich foods.

For example, on red days when you can have a large portion of meat fish etc you're only allowed controlled amounts of high fibre carbohydrates, not just any carbohydrate. Left to us we would probably choose to have white pasta with our meat on a red day but the restriction of healthy extras forces us to have high fibre foods like wholemeal pasta and such.

Also, because the eating plan is all about abundance and eating generously, it would be very easy to overdo things if we could eat meat AND carbs freely within a meal. So again, therein lies the "hidden" restrictions lol. Even with the new Extra Easy plan allowing this, we have to have at least 1/3 superfree vegetables within the meal to prevent overeating and to allow us to have the necessary vegetables we could so easily forget in the face of a yummy spaghetti bolognaise!

So basically the whole eating plan is structured in a way that ensures we get the right amount of nutrients without being too restrictive. It allows us to eat satisfying amounts of the right kinds of food which has been proven to be very effective because as we all know the #1 way to ruin a weight loss plan is the feeling of deprivation!
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Thanks everyone for the well written and thoughtful replies. So much better than 99% of other forums I visit!!!!

So it seems that the whole red/green thing is simply 2 effective low cal/low fat diets that individuals are free to swap as and when they please to give variety.

Not sure that's great for the long-run but that just me!! :rolleyes:

BTW the old Haye thing has been scientifically disproven years ago! Basically the original idea was this...

Protein is broken down by acid
Carbs are broken down by alkaline

Both these facts are true.. but since you can't have both at the same time it was theorized (by Dr. Haye) that you should only have protein or carbs on any one day to allow your stomach to be one or the other.

It was cutting edge science 100 years ago but is now proven to be worng as you stomach is acid and your intestines are alkaline (where the fats and carbs) are broken down (with the help of bile).

But once again thanks for your responses everyone.. its been very useful.

BTW I'm not trying to lose weight but I am trying to support soemone who is.


Lover of Extra Easy
S: 11st8lb C: 10st6lb G: 9st6lb BMI: 25.9 Loss: 1st2lb(9.88%)
So it seems that the whole red/green thing is simply 2 effective low cal/low fat diets that individuals are free to swap as and when they please to give variety.

Not sure that's great for the long-run but that just me!! :rolleyes:
And then you have Extra Easy where you have can have whatever is free on both red and green, and whatever is syned, always take the lower value!

And it is great for the long run, as it's normal healthy eating and very sustainable
as it's never boring and you can eat a lot!

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