Healthy Evidence

If sugar is bad for you, Is there any evidence to suggest low fat milk is healthier than full fat?

There is a lot of news regarding sugar in the press and it's health consequences. The NHS suggests we cut fat, such as switching to low fat milk which will inadvertently raise the amount of lactose we consume, is there evidence to suggest low fat milk is healthier than full fat?

44 Replies

Hi Andrew,

Sugar isn't bad for you, the body uses glucose (a simple sugar) as its primary fuel source. In the same way fat is essential for a healthy body. However, as with most things you can have too much of a good thing. By drinking low fat milk you are reducing your fat and calorie intake. So, if you are watching your weight semi-skimmed milk may be considered "healthier" but in small quantities whole milk is not unhealthy.

As for lactose, in the vast majority of people it is either broken down and absorbed into the body or excreted undigested without any adverse effects. In some cases people are intolerant to lactose but this is the exception rather than the rule.

Hope this helps.


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Cheers, I was after evidence of the reasons behind it. I found this Pdf about how to fatten pigs and it recommends using skimmed milk and grain.



Hi Ian, I agree.

I think when it comes to "healthy eating" we often deal far too much on particular issues and not enough on just quantity.

For me (as an overweight person) the real, logical problem is that generally in society we eat too much of everything; it is bulk that is the issue. Trying to make villains out of any particular food source is ignoring the science behind how the body actually works, what it is designed to cope with and so on.

So, back to milk, the benefit of drinking a milk with less fat is going to be very much based on how much you drink. My partner drinks a hell of a lot of tea with milk plus her breakfast cereal, so she benefits from the lower fat milk. I drink black coffee and have milk just occasionally, so I do not benefit from the lower fat milk varieties.

I imagine that there is an argument that depending on your overall fat and sugar intake, for some people drinking whole milk may actually be better!


I was wondering why feed pigs milk and grain to make them fat, (that's the standard UK breakfast) , and not just grain. And why skimmed milk over full fat. Some say the fat in the milk helps satisfy your appetite and sugar doesn't have any effect.


I am never totally sure what having your appetite satisfied actually means. Feeling full? Hitting a taste saturation point? Getting dizzy from too much sugar? And why do some people seem to have "had their fill" far sooner than others?

As for the pigs, try this article:

Though I am not sure about making diet comparisons with a beast that, for one reason or another, is not expected to have a particularly long life!


Could there be economics at play? I'd imagine that most milk sold in the UK is semi-skimmed and therefore perhaps that's cheapest available in bulk to feed to pigs. As an aside, when I was a student I worked at a dairy farm that used the going-out-of-date ice cream to feed the pigs! Pretty sure it was full fat, but it made economic sense for the farmer.


I find it interesting that the NHS recommends a breakfast that is considered perfect for fattening live stock. I know we're not live stock but there must be some similarities.

Rob, do you have evidence to support the NHS advice?


Sorry Andrew, I'm confused which advice are you referring to?


And is there anything wrong with recommending something just because we feed it to animals? We feed chickens wholegrains after all!


Hi Rob

As this was the healthy evidence forum I was looking for evidence to support the NHS claim that changing from full fat to low fat milk will help me lose weight.

I've stumbled around the Internet trying to get a definitive answer on this and thought this forum could help. I understand this is an evidence forum, and I was hoping to find some.

I told my wife that skimmed milk doesn't make a difference to weight gain, so far I can't prove it either way. But I did find the skimmed milk and animal feed and thought that sounded interesting.


Do you have a link so I can look into it?


Do you mean this ? If so, I imagine that the advice is based on reduced fat content and therefore fewer calories. I can check.


Hi Rob

It was the tweets I was receiving from change 4 life and I just wondered what evidence they had for it.


Ahh - Change4Life is a campaign run by the Department of Health - so not something I deal with. You can contact them to #askforevidence here:

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Cheers Rob. I'll check with change 4 life.

Could you supply the evidence that the NHS used in the web page regarding the choice of lower fat milk being better for you than full fat.



Change4Life said they received information from Public Health England and could not tell me any more than that.

I now understand that skimmed milk is preferred over full fat because of the saturated fat content.

This is my email to them:

Dear Sir/Madam,

Please could you send me the evidence that the Chang4Life health campaign have used in relation to lowering saturated fat.

I am currently on a high fat diet and a little worried, but as I appear healthy I would like to know the facts before I make the Change4Life swaps that have been advised.




But where is the evidence that saturated fat is bad for you?

Several meta-studies have found lacking or no support for this "lie" which was based on the totally debunked Seven Countries Study.

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Hi Andrew

Here is an interesting article about the arguments over saturated fat:

It is not an authoritative piece, but you could use it for tracking down any articles written by the various professionals quoted to find fuller explanations.

Generally speaking, if you want to add fat to your diet, Olive Oil seems to have been keeping the Mediterranean people going happily for centuries! :) But like everything else, balance is what your body really craves.


It looks like that page was based on advice originally produced by the Food Standards Agency so I don't have the list of references available. It has since been checked against NHS Evidence, and signed-off by a dietitian and Department of Health policy as per our standard editorial process.

I'd hazard a guess (I'm sticking my neck out here) that lactose hasn't been considered in particular, but that fat (and therefore calories/joules) were the main focus of the health advice.

Do you have any relevant links to info on lactose in skimmed/semi-slkimmed milk? The Dairy Council (admittedly not an unbiased source) says that the levels of lactose are roughly the same


I assume the amount of lactose does not change in quantity for different milk types because it is not part of the fat but a sugar that is present in the whey. It contributes about 30% of milks calories (since it is a sugar) which is why even skimmed milk has a calorific value of 34/100g.

I think I have that about right. Here is something useful to get your teeth into:


I have read that fat will lower the GI affect of carbohydrate. Now if you are eating cornflakes with skimmed milk surely you will have a higher insulin spike than with full fat milk. I'm unsure whether this is unhealthy or not.

I would like to add I'm a builder not a scientist, but I'm just trying to understand the reasoning behind it all.

Protein/fat: Adding protein or fat, which have minimal effects on glycemic excursions, to a high-GI food will decrease the GI of that food. For example, adding cheese to a slice of bread would decrease the GI.



Hi Andrew

According to the US Department (which has a very useful database for such things), full fat milk has 61 calories per 100g with 3,2g fat, semi-skimmed (2%) has 50 calories and 2g fat and skimmed has 34 calories and 0.1g fat.

So, if you are counting calories, then skimmed milk has less of 'em.

A useful tool is typing questions into Google like "how many calories in milk" - this brings up the Google knowledge base which uses sources like the USDA and gives a lot of nutritional facts.

The USDA database is here:

There is a sort of uk one, but as far as I can work out it is 12 years out of date ....


But what if calories don't make you fat? Which was why I was after the evidence.

I have seen several reports showing that low fat diets handle calories in a different way to higher fat diets.

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The quantity of lactose varies only very slightly in whole, semi- and skimmed milk ( ). However, there are fewer calories in semi-skimmed and skimmed milk than in full-fat milk, so it's not unreasonable to suppose that switching might help with weight control, and most of us are overweight.


But what if the fat in the milk helps satisfy hunger. I was looking for Evidence.

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Great you are asking for evidence. We've asked a dietician to join in the discussion.




Perhaps someone who is well versed in this area might find it interesting to look at this blog post and the papers referenced: armadillokerfuffle.blogspot...

The quoting of a nutritionist concerns me, but some of the other stuff sounds reasonable. I'm really not able to comment myself on the quality of the papers or the interpretation of them, but thought it might be relevant to this discussion.

I hope it's ok to pop this here even though I'm not sure how good the information is.

I must say some of the stuff from the same author on vaccines is a bit worrying but I still thought the references might be of interest so I thought it worth putting the link here.


Many thanks for that.


The main thing to realise about almost all questions about diet and health is that we just don't know. The reasons for that are explained at

That's why the subject is so riddled with fads and evangelism.

There is no reason to think that sugar is poisonous. It's just that when it's added to everything, it makes it very easy to eat too may calories.

The great problem that is is whether or not eating a lot of sugar CAUSES diabetes. If it did then excessive sugar could validly be described as poison. But as far as I know, this has not convincingly shown.

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Cheers, I understand that.

But does that mean there is no evidence to suggest that skimmed milk is better for you than full fat?


I doubt whether there is any evidence at all about that. I'd stop worrying and just eat a variety of things, and not too much of any of them.


I was beginning to think that.

So I've asked for evidence, and there probably isn't any.

It should be called Change4ChangesSake


I think there is plenty of evidence around that says if you eat too much in the way of calories, you will get into trouble. If you eat too much fat that your body cannot cope with, you will get into trouble. And so on.

So, I think the advice given on sites like Change 4 Life is very good, balanced and devoid of the often unproven fringe arguments that might sell a lot of books but probably do little for people's health.

When looking for evidence, the first rule is to check the authority of the organisation giving advice. And the UK's NHS service (despite the efforts of some news services) is regarded as one of the worlds best health systems with some of the best medical professionals you will find. That does not mean that they know everything or will have all the answers you require, but it is a pretty solid place to start when looking for good advice.

Meanwhile, back to your milk issue. As someone who needs to lose a huge amount of weight, the last thing I need is to throw more calories or saturated fat at my problem. So, drinking 2% or 1% milk seems one thing that is at least simple to do without me feeling like I am missing something. I only wish cutting down on other foods was so simple!


Hi JossS

I imagine the NHS get dietary advice from somewhere, so I'm interested where.

But there are other places to look also. If you have time it would be well worth checking these out:

A very interesting book: Why We Get Fat: And What to Do About It by Gary Taubes.

These "amateur scientists" give a convincing argument saying that full fat would be better for you and I'm hoping that the department of health can also give an equally convincing argument saying why it isn't. I'm not sure if these links qualify as evidence, probably not, but sometimes you have to make up your own mind.

I've switched to Low Carb High Fat and have lost weight. But I am also concerned that I am going against NHS health advice. I have been LCHF for 4 months and decided to have my cholesterol checked by the doctor today. I should have the results back next week. I am a little concerned about giving advice to my wife that goes against the NHS advice. Hence the original question.

Anyway good luck with your weight loss goals.

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Results back.

According to this I have a low risk of a heart attack. 239 and HDL of 76.

So far I have lost weight, felt better and have a low risk of a heart attack. So why is full fat bad. Still no evidence yet. Still searching.

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To the original question. Is some sugar bad for you: NO. Is too much sugar bad for you: YES. So the question is how much sugar can I eat /population eat, with minimal health risk consequences? Again, the answers will vary slightly depending on whether the health factor considered is dental caries or type 2 diabetes. As a general reference figure, guidelines suggest no more than about 90g per day of total sugar. Skimmed milk contains, per 100g: cals 32, sat fat 0.1 and lactose 4.4g whole milk contain, per 100g, 66kcals, sat fat 2.5 and lactose 4.5g. So skimmed milk is much lower in energy and saturated fat, but there is no significant difference in sugar (lactose) content.

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The question was, where is the evidence that skimmed milk is better for you than full fat.

There are so many different factors at play. Skimmed milk is higher on the gi scale than full fat, some people would agree that was detrimental. But some say saturated fat is bad for you so that would make full fat worse.

The calorie content should not matter as you could just drink less of it.

Choices4change have made the statement I was wondering what the thinking was behind it. And of course the difference is very minor between them so why pick on milk?


See this programme next Wednesday (29th) on BBC2

Horizon - "Sugar v Fat" presented by Doctors Chris and Xand van Tulleken


Cheers JossS,

I'm really looking forward to seeing this. I could guess which way it's going to go. It looks like it will be very similar to the Sam Feltham experiments. None of these will unfortunatley prove anything as the study is too small.


I've had a reply from the Department of health:

Thank you for your correspondence of 21 January about the Change4Life campaign. I have been asked to reply.

As part of the Government’s plans to improve the public health system, the Change4Life campaign is now part of Public Health England (PHE), an executive agency of the Department of Health.

Therefore, I have forwarded your email to PHE and asked it to respond to you directly. For your information, PHE’s contact details are:

Public Health England

5th Floor

Wellington House

133-155 Waterloo Road

London SE1 8UG

Tel: 020 7654 8000


Yours sincerely,

David Segar

Ministerial Correspondence and Public Enquiries

Department of Health


I have had a reply from PHE.

Here is the evidence I have been searching for. I'm not sure how long it will take me to go through it or whether I'll understand it.

Being on a LCHF diet I am going against this advice. This is why I started the search so I can hopefully make my own mind up.

Dear Andrew,

Thank you for your recent email to the Department of Health regarding the Smart Swaps campaign. As your email refers to a campaign run by Public Health England, we have been asked to reply.

Data from the national diet and nutrition survey clearly demonstrates that we are all eating too much salt, saturated fat and sugar. Such intakes are associated with a risk of being overweight, obesity, cardiovascular disease, diabetes and some cancers. Helping people to choose, cook and eat a diet lower in salt, saturated fat and sugars (and higher in fruit and veg, fibre and oily fish) will lead to longer, healthier lives.

Government advice to limit saturated fat intake to no more than 11% of total food energy in order to reduce the risk of cardiovascular disease is based on long standing evidence from the Committee on Medical Aspects of Food Policy (COMA) and is endorsed by the Scientific Advisory Committee on Nutrition, who now provides the UK with independent advice on nutrition. The advice is supported by a wealth of evidence and is also in line with more recent assessments made by the Institute of Medicine (2005), World Health Organisation (2008) and the European Food Safety Authority (2010). There is good evidence from randomised controlled trials (RCTs) to demonstrate that saturated fat consumption influences cholesterol levels and increases the risk of cardiovascular disease.


Bates B, Lennox A, Prentice A, Bates C, Swan G (2012) National Diet and Nutrition Survey

Headline results from Years 1, 2 and 3 (combined) of the Rolling Programme (2008/2009 – 2010/11). Available at:

EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol. EFSA Journal 2010; 8(3):1461.

IOM (Institute of Medicine). 2005. Dietary Reference Intakes for Energy, Carbohydrate,

Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academies of Science, Washington DC.

WHO. 2008. Fats and fatty acids in human nutrition. Joint FAO/WHO Expert Consultation. Food and nutrition paper 91, WHO, Geneva.

I hope this information is helpful.


I found this interesting in the EFSA panel report:

Saturated fatty acids

SFA are synthesised by the body and are not required in the diet. Therefore, no Population Reference Intake (PRI), Average Requirement (AR), Lower Threshold Intake (LTI), or Adequate Intake (AI) is set.

There is a positive, dose-dependent relationship between the intake of a mixture of saturated fatty acids and blood low density lipoprotein (LDL) cholesterol concentrations, when compared to carbohydrates. There is also evidence from dietary intervention studies that decreasing the intakes of products rich in saturated fatty acids by replacement with products rich in n-6 polyunsaturated fatty acids (without changing total fat intake) decreased the number of cardiovascular events. As the relationship between saturated fatty acids intake and the increase in LDL cholesterol concentrations is continuous, no threshold of saturated fatty acids intake can be defined below which there is no adverse effect. Thus, also no Tolerable Upper Intake Level can be set.

The Panel concludes that saturated fatty acids intake should be as low as is possible within the context of a nutritionally adequate diet[1]. Limiting the intake of saturated fatty acids should be considered when establishing nutrient goals and recommendations.

This study would contradict the one above.

Most heart attack patients' cholesterol levels did not indicate cardiac risk

Among individuals without any prior cardiovascular disease or diabetes, 72.1 percent had admission LDL levels less than 130 mg/dL, which is the current LDL cholesterol target for this population. Thus, the vast majority of individuals having their first heart attack would not have been targeted for effective preventative treatments based on the criteria used in the current guidelines.

The team also found that half of the patients with a history of heart disease had LDL cholesterol levels lower than 100 mg/dL, and 17.6 percent of patients had LDL levels below 70 mg/dL, which are guideline targets for LDL cholesterol in those at fair risk and at high risk for cardiovascular disease, respectively.


Andrew, keep eating what you're eating. The SAD/SUKD is not a heart healthy diet although they tell us it is. Full fat milk is way better than skimmed or semi skimmed, raw milk is better than homogenised, pasteurised etc. Why do we keep tampering with things that have kept humans healthy for millennia. Full fat will buffer any insulin spike from the lactose in the milk, as will full fat yoghurt. It will slow the glucose release in the blood. The fat in milk/yogurt/cheese carries fat-soluble vitamins and minerals. Without that fat, you don’t get those vitamins and minerals. Particularly, your body needs fat in the yoghurt to use the calcium in that yoghurt. Both calcium and iron need fat in the food to be available to your body. Also, the various fatty acids in the fat are important to your body. One of these, conjugated linoleic acid, or CLA, plays a vital role in signalling your body to retain healthy, lean muscle tissue. It is sold as a bodybuilders’ supplement. Why let the manufacturers take away the valuable nutrition in those fats?

Also one comment is wrong. Glucose is the only thing that can be manufactured by the body via gluconeogenisis. There has been a grave misunderstanding between needed carbohydrates and glucose needs. Carbs are in fact glucose chains!!!!! We don't NEED to eat them to provide our glucose. But life would be boring without them so choose green and colourful veggies over starchy root vegetables, and berries and cream for desert.


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