Low-fat vs Full-fat products

There are so many questions around low-fat vs full-fat products. We attempt to answer many of them in this blog. Such as:

Which is better?
Which is healthier?
Which is more likely to help you lose weight?
Do low-fat products make you gain weight?

At first glance, you may think low-fat products are healthy since they have less fat. You may have heard of research linking heart disease and type 2 diabetes to saturated and trans fats. Let’s look at the research to answer some of these questions.

Let’s first look at what qulifies as a low-fat product. For solid foods, they need to contain 3g or less fat per 100g. For liquids, they need to contain less than 1.5g fat per 100ml

To first understand the benefits or pitfalls of low-fat products let’s see how low-fat products are produced and what they contain.

Typically you will find many extra additives in a low-fat product when compared to its full-fat counterpart. The most common additives you will find will be:

Thickeners – A low-fat product is typically more liquid, therefore thickeners are often added
Sugar – to make the product more palatable, sugars are often added

It makes sense that to create a low-fat product, more processing is required, taking the food further away from its naturally occurring state. That in itself is concerning since our aim is to try to eat food as close to its naturally occurring state as possible.

The other issue is that fats play an important part in our overall nutrition. Stripping fats out of our diet is not a necessarily a good thing. Some of the roles of fats are:

assist to metabolise fat-soluble vitamins
play a role in the immune system
provides structural material for cell membranes and
required for the nervous system to function properly
assist cell membrane receptors, including receptors for insulin
involved in inter-cellular communication

Low-Fat vs. Full Fat Products Research

Let’s review the research and firstly see if the link between full-fat dairy products and cardiovascular disease is true.

Full-Fat Products Research

A study led by Dr. Dariush Mozaffarian, from the Friedman School of Nutrition Science and Policy at Tufts University in Boston in July 2018 claims that full-fat dairy does not raise cardiovascular risk. In fact, due to the fats present in some dairy products, they may protect against stroke and heart disease.

Medical News Today summarised the studies findings:

To study the effect of dairy on mortality risk and cardiovascular health, Dr. Mozaffarian and team examined over 2,900 U.S. seniors, aged 65 and above.

The researchers measured the participants’ blood plasma levels of three fatty acids contained by dairy products at the beginning of the study in 1992, 6 years later, and then 13 years later.

Associations with “total mortality, cause-specific mortality, and cardiovascular disease (CVD) risk” were examined.During the 22-year follow-up period, 2,428 of the participants died. Of these deaths, 833 were due to heart disease.

However, none of the three fatty acids examined correlated with the risk of total mortality. In fact, high circulating levels of heptadecanoic fatty acid were associated with a lower risk of death from heart disease.

Also, adults with higher levels of fatty acids overall were 42 percent less likely to die from stroke, revealed the analysis.
source: Medical News Today

Lets now look at a study conducted by the Federal University of Rio Grande and the University of Minnesota with the objective to see if dairy products may have beneficial cardiometabolic effects. the study concluded:

Total and Full-Fat, but Not Low-Fat, Dairy Product Intakes are Inversely Associated with Metabolic Syndrome in Adults
Total and especially full-fat dairy food intakes are inversely and independently associated with metabolic syndrome in middle-aged and older adults, associations that seem to be mediated by dairy saturated fatty acids. Dietary recommendations to avoid full-fat dairy intake are not supported by our findings
Source: PubMed

In layman’s terms, the research suggested that full-fat dairy products have a beneficial effect on metabolic syndrome. Metabolic syndrome as defined by Victorian Government Better Health Channel: is a collection of conditions that often occur together and increase your risk of diabetes, stroke and heart disease. The main components of metabolic syndrome include obesity, high blood pressure, high blood triglycerides, low levels of HDL cholesterol and insulin resistance.

Research conducted by the University of California San Francisco aimed to show a link between milk fat consumption and severe obesity among three-year-old Latino children, a population with a disproportionate burden of obesity and severe obesity.

145 children partook in the study of whom 17% were severely obese. The severely obese children had a lower mean intake of milk fat (5.3g vs. 8.9 g) and 79% drank any milk (as compared to 95%

Data was available for 145 children, of whom 17% were severely obese. Severely obese children had a lower mean intake of milk fat (5.3 g vs. 8.9 g) and fewer drank any milk (79% versus 95% for not severely obese children (p < 0.01)).

The evidence suggests that full-fat milk consumption actually reduced the likelihood of childhood obesity in Latinos. Specifically, the study concluded:

Higher milk fat consumption is associated with lower odds of severe obesity among Latino preschoolers. These results call into question recommendations that promote consumption of lower fat milk
Source: PubMed

Here in Australia, the CSIRO conducted research to see if there was a link between dairy and weight loss. They found that dairy consumption in the context of controlled calories may actually enhance weight loss and body composition changes. 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

A study conducted by Lund University, Sweden in May 2015 aimed to look at the role of dietary fats and their affect glucose metabolism and obesity development to determine if they play a role in type 2 diabetes.

The study wanted to validate studies that indicated replacing saturated with unsaturated fats might be favourable, and plant foods might be a better choice than animal foods. However, the study concluded that dairy foods are protective. Specifically the study concluded:

Decreased type 2 diabetes risk at high intake of high- but not of low-fat dairy products suggests that dairy fat partly could have contributed to previously observed protective associations between dairy intake and type 2 diabetes. Meat intake was associated with increased risk independently of the fat content.
Source: PubMed

In layman’s terms, full-fat dairy was linked to decreased risk of type 2 diabetes. However, this was not the case with low-fat dairy products. Suggesting that dairy fat may be protective against type 2 diabetes.

Low-Fat Products Research

As I suspected, there is less research about the affect of low-fat products due to limited funding available to conduct this research. I did however, find some.

The University of Toronto aimed to determine if low-fat foods did contain fewer calories than their full-fat counterparts. However, the study concluded that most of the low-fat products did not contain fewer calories than their full-fat counterparts.

The national post summarised the findings:

“But you can have a food that is, on average, almost 50 per cent lower in fat, but has virtually no change in calories.
“Food manufactures are removing the fat, absolutely,” she said. “But they’re putting in other components, other ingredients (such as sugar) and in the end, that food has just as many calories.”
The study, led by Alyssa Schermel, was based on a database containing food label nutrition information for a total of 10,487 products, representing 75 per cent of the grocery retail market share. In all, nearly 6,000 foods were included in the final analysis.
Source: The National Posts

The Telegraph in the UK conducted a study of food and drink products marketed as “low fat” and found they contain excessive sugar levels.

Many low fat foods promoted as healthy-eating options contain more sugar than their “full fat” equivalents – in some cases more than five times as much, an analysis by The Telegraph shows. The disclosures come after the World Health Organisation (WHO) said that the daily allowance for a person’s intake of added sugar should be halved to six teaspoons to help avoid mounting health problems including obesity and tooth decay.
A study of 100 popular low or non-fat grocery items from major supermarkets found that dozens contained at least two teaspoons of total sugar in a single serving. One in four of the products contained more than three teaspoons of the ingredient.
Experts said the Telegraph’s findings showed how “low fat” and “low calorie” products could often have more harmful effects on health than their “full fat” equivalents. They believe high levels of sugar are contributing not just to rising levels of obesity, but also other health conditions such as diabetes, heart disease, dental cavities and cancer.
Source: Telegraph

In addition, a study conducted at Baker Heart and Diabetes Institute, Melbourne in 2015 concluded that:

short-term diets containing low-fat dairy products did not lead to a more favourable biomarker profile associated with cardiovascular disease risk compared with the full-fat dairy products, suggesting that full-fat fermented dairy products may be the more favourable
Source: PubMed

A study conducted by the University of Georgia in July 2017 attempted to examine the effects of a low-fat diet food on rats. The rats were fed a diet high in sugar but low in fat (meant to imitate popular low-fat diet food). the result was an increase in body fat mass when compared to rats fed a balanced rodent diet. In addition, the high-sugar diet resulted in a number of other health problems in the rats including brain inflammation and liver damage.

Science Daily reported:

“Most so-called diet products containing low or no fat have an increased amount of sugar and are camouflaged under fancy names, giving the impression that they are healthy, but the reality is that those foods may damage the liver and lead to obesity as well,” said the study’s principal investigator, Krzysztof Czaja, an associate professor of veterinary biosciences and diagnostic imaging in UGA’s College of Veterinary Medicine.
“What’s really troubling in our findings is that the rats consuming high-sugar, low-fat diets didn’t consume significantly more calories than the rats fed a balanced diet,” Czaja said. “Our research shows that in rats fed a low-fat, high-sugar diet, the efficiency of generating body fat is more than twice as high — in other words, rats consuming low-fat high-sugar diets need less than half the number of calories to generate the same amount of body fat.”
Source: Science Daily

Summary

Are low-fat products better for your health and for weight loss?

The research suggests that full-fat dairy may actually be beneficial (protective) to on obesity, diabetes, stroke and heart disease.

In addition, low-fat products may contain additional additives such as thickeners and sugar and may not necessarily be lower in calories. In addition, research suggests that low-fat products may decrease satiety and lead to increased caloric consumption and weight gain.