Medicine

Dairy and weight loss

“Milk was a bad choice!” – so were the words of the legendary Ron Burgundy after consuming a carton of the stuff on a particularly hot day.

When it comes to weight loss and diet, the common thinking is that Ron’s words hold true: dairy has often been thought to be fattening. But a recent comprehensive scientific review we completed found that dairy consumption in the context of controlled calories may actually enhance weight loss and body composition changes.

So hang on a tic, you ask, do we need to be consuming dairy products if we want to lose weight? NO! is our answer. There is no one-size-fits-all (excuse the pun) solution we are advocating here – for various reasons, you may prefer a different dietary route to weight loss. But, for many people, increased dairy intake can help knock off the kilos while still staying healthy.

Here’s what you need to know.

What’s an energy-restricted diet?
An energy-restricted diet is another name for a low-calorie diet. Your body needs calories for energy, but eating too many calories can lead to weight gain. Cutting out foods high in fat and sugar to reduce excess calorie intake is a massive help when losing weight.

So what’s dairy got to do with it?
If you are overweight, the general goal for optimal weight loss is to reduce body weight by reducing fat mass, while minimising loss of lean mass (ie muscle and other non-fat body components). But low-calorie, energy restricted diets often result in a concurrent unfavourable lean mass reduction, which can account for around 20% of total weight loss. Retaining lean mass, particularly its skeletal muscle component, is important for regulating resting energy expenditure, protein metabolism and glucose uptake

Dairy contains several nutrients and bioactive components that can help retain lean mass under conditions of weight loss. In particular, dairy is a rich source of calcium that reduces absorption of fat; proteins (whey and casein) that promote muscle protein synthesis, and regulate appetite; and fatty acids that affect energy balance through reduced fat synthesis, increased fat breakdown and by regulating appetite.

But aren’t dairy foods full of fat?
Dairy foods are generally high in fat, but not always – regular milk is about 50% fat by energy, while skim milk has a very small amount. However, dairy foods are also a good source of many nutrients – including calcium, phosphorus, magnesium, potassium, iodine and vitamin B12. In the context of this review, studies using low fat or regular dairy foods had a similar beneficial effect on weight loss.

What did our research find?
We searched 5 global databases of scientific journals to find the results of all experimental studies investigating the effects of consuming dairy food or dairy supplements during energy restriction on body weight and composition in 18-50 year-olds. The studies showed that consuming dairy food or supplements as part of an energy restricted diet resulted in around 1.5 kg greater loss in fat mass compared to consuming a diet low in dairy. About 90% of the study participants were women, and those who consumed more dairy also managed to retain 75% more lean mass compared to those consuming low dairy diets.

The results did not differ between studies that used whole dairy foods versus dairy supplements, or between studies that specified the use of low-fat or skimmed dairy products compared to those that did not specify the product type. Hence, either regular fat dairy food, low fat dairy food or dairy supplements can be consumed as part of an energy restricted dietary intake to get additional fat loss benefit.

So I’ve cut out down on my calories but want to retain my lean mass weight. How much dairy (or dairy supplements) should I be eating?
The results were achieved by consuming more than two servings of whole dairy food daily or 20-84 g of whey protein per day for an average of 16 weeks as part of a low calorie diet. A serving of dairy equals a glass of milk, 200g yoghurt or 40g cheese.

Will this work for blokes too?
Since the majority of participants examined in the studies were women, further research in men is required to be sure that the effect is the same in men as it is in women.

Wasn’t this research funded by the dairy industry?
Yes it was – you can read our full findings here. Rest assured we stand by our findings: we only publish high quality scientific information which is subjected to robust peer review, in papers, reports and otherwise. We apply high standards for the responsible conduct of scientific research; and at all times we maintain our reputation for integrity and scientific impartiality and independence.

So what’s the one-line takeaway from this?
If you’re an overweight or obese woman aged 18-50 years on an energy-restricted diet and you’re not lactose-intolerant or allergic to dairy protein, dairy food consumption as part of your diet can help you lose more weight from the right places.

Find out more about our work in this area.

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