5 Nutrition Myths That Need To Stop
“A widely held, but false belief or idea.”
“A fictitious or imaginary person or thing.”
“An exaggerated or idealised conception of a person or thing.”
We can’t escape nutrition advice. Daily advice is often dispensed from numerous sources, but suitably accredited nutrition professionals are often not heard.
Should we not be taking a step back and thinking about whether the advice received is credible? Is the advice backed by scientific research or is it purely anecdotal? Does it fit a certain agenda? What qualification does the person dispensing the advice hold? Have they specifically studied a recognised nutrition degree at university?
I shall talk through five of the most common nutrition myths that refuse to go away and we shall see how they stand up to scientific scrutiny.
Sometimes our firm held beliefs can cloud our judgement. I hope that the following content, drawing upon the scientific literature, can help inform your nutrition knowledge and avoid the common nutrition myth pitfalls.
Myth 1: There Is No Single Best Diet For Fat Loss
Shall I let you in on the real nutrition truth? There is no single magic weight loss diet …
All dietary approaches that bring about weight loss certainly have one thing in common – they place you within a negative energy balance (deficit), where energy intake is less than energy expenditure.
It has become all too predictable when reading the setup of the latest self-proclaimed ‘best diets’. The notion of calories and energy balance is questioned, yet they will subconsciously require you to reduce your caloric intake and thereby create a negative energy deficit. All choices will therefore lead to the desired outcome of weight loss within individuals without medical complications.
Low Carb & High Fat or Low Fat & High Carb
The elimination of a food group (carbohydrates or fat) = restriction upon dietary choices = restriction of calories
Intermittent Fasting or Alternate Day Fasting
Fast and eat within certain hours of the day = restriction upon dietary choices = restriction of calories
The elimination of sources (e.g. gluten/dairy containing) and inclusion of ‘clean’ sources = restriction upon dietary choices = restriction of calories
The attachment of points to certain foods and a budget given upon daily calorie intake = restriction upon dietary choices = restriction of calories
Although leading to weight loss, such diet approaches can be unnecessarily restrictive upon dietary choices, which do not take into account personal preference, activity levels, genetics and individual tolerance.
Typically dieters will regain a certain amount of weight lost post-diet and therefore longer-term weight management and dietary adherence becomes an issue. Is this not why personal preference should be valued?
Don’t get me wrong; benefits can be drawn from the example diets opposite. Within Paleo, an emphasis upon quality protein and healthy fat sources and the regular inclusion of salad/vegetables is a great choice. However, it’s the elimination of certain food sources based upon a lack of scientific evidence/clinical diagnosis that provides an unnecessary dietary restriction, which could compromise adherence and long-term weight management.
“What about the quality of the diet?”
This is obviously also important with regards to health and weight management. Adequate protein inclusion within a diet is essential for maintenance/growth of muscle mass. When dieting increasing protein intake is important for maintaining/increasing muscle mass. Additionally, the inclusion of increased protein will aid satiety and provide elevated energy expenditure via the thermic effect of feeding and maintenance of muscle. The size of the calorie deficit will also impact upon rate of weight and muscle loss. Ensuring sufficient fat, carbohydrate and micronutrient intake are also important considerations.
Myth 2: Small Regular Meals Boost Metabolism
How many times have you heard this before?
Such advice is constantly repeated when individuals are starting out on their weight loss journey, but is this actually true?
Metabolism – What is it?
Quite simply, metabolism refers to the chemical reactions within the body in order to maintain life. The amount of energy an individual expends daily is otherwise known as ‘Total Daily Energy Expenditure’ (TDEE). TDEE encompasses 4 components:
1. Resting Metabolic Rate (RMR) – the energy you are expending sat there right now to maintain life whilst you read this.
2. The Thermic Effect of Food (TEF) – otherwise known as ‘Diet Induced Thermogenesis’ (DIT). This is the energy expended through the digestion, absorption and storage of food.
3. Exercise Activity Thermogenesis (EAT) – energy expended through planned exercise.
4. Non-Exercise Activity Thermogenesis (NEAT) encompasses energy expended during non-planned exercise activity (e.g. walking around work) and spontaneous activity (e.g. fidgeting).
Thermic Effect of Food (TEF)
The suggestion that regularly eating meals will enhance metabolism is based upon the belief that increasing the frequency of TEF stimulation will elevate overall TEF contribution to total daily energy expenditure. TEF typically contributes approximately 10-15% of TDEE depending up the macronutrient composition of daily intake. However, when calories/macronutrients are matched there is no difference in overall TEF between a frequent or less frequent feeding pattern.
The image above provides an example overview of 5 small regular meals vs. 3 larger less frequent meals, where total calories/macronutrient consumption is matched.
However, it is important to acknowledge that there may be certain situations that may benefit an increased meal frequency:
- Personal preference e.g. may aid appetite or be psychologically beneficial.
- Athletic individuals should utilise an approach that also considers their training/performance goals and demands.
- Caloric intake may be high and less frequent larger meals may cause gastro-intestinal discomfort e.g. bloated feeling.
When creating your dietary approach remember, eating “little and often” does not “boost your metabolism” when compared to diets matched in total calories/macronutrient contribution. When deciding upon your meal frequency utilise an approach that suits your schedule, demands and personal preference.
Myth 3: Dairy Is Bad For Your Health
It almost seems fashionable now to remove dairy from our diet doesn’t it? Some individuals are reaching for the almond and coconut milk, based on the assumption that this is the ‘healthier alternative’. However, could they be missing out on the potential benefits to health that dairy products provide?
Lactose Intolerance: What Is It?
Dairy products such as cheese, milk and yogurt, contain the sugar lactose. Lactose is broken down into smaller sugars glucose and galactose (monosaccharides) by the enzyme lactase within the small intestine.
However, following the first few months of human life the activity of lactase decreases within some individuals resulting in ‘lactase non-persistence’. Undigested lactose within the small intestine is then fermented by bacteria within the colon, leading to the production of gas (methane, hydrogen and carbon dioxide) and the typical symptoms of bloating, flatulence or abdominal pain. Additionally, an increased intestinal osmotic load (increase in intestinal water) may occur which can lead to diarrhoea.
The implementation of a FODMAP (Fermentable Oligosaccharide Disaccharide Monosaccharide and Polyols) Diet by clinical professionals is increasing utilised to treat individuals with IBS (Irritable Bowel Syndrome). Due to the fermentation of short chain carbohydrates within the gut causing gastro-intestinal complaints a withdrawal of lactose intake may be incorporated.
It is important to consult an accredited medical professional (e.g. dietitian or doctor) with regards to lactose intolerance diagnosis/treatment.
Should We All Be Avoiding Lactose?
Although ‘lactase non-persistence’ is typically observed following the first few months of life, ‘lactase persistence’ has been found within individuals. This is thought to be related to the domestication of cattle and increased production/consumption of dairy leading to a regulatory genetic mutation as humans evolved. To quote the research, “up to 70% of the world population has lactase non-persistence, but not all are intolerant to lactose as many nutritional and genetic factors influence tolerance … Ethnic origin affects the frequency of lactose intolerance. In adults, white North Europeans, North Americans and Australians have the lowest rates ranging from 5% in British population to 17% in Finland and Northern France.”
Although, lactose restriction is a common treatment for diagnosed lactose intolerance, individuals may tolerate lactose amounts of up to 12g without any adverse side effects, especially if spread throughout the day. Furthermore, fermented dairy sources are an alternative due to a lower lactose content within cheese and live cultures (bacteria) present within yogurt to aid lactase activity and lactose digestion.
Dairy and Acid-Alkaline Balance
It is claimed that dairy consumption increases dietary acid load due to its protein and phosphorus content, which is suggested to compromise bone health as a result of increased urinary calcium loss. However, urine calcium does not reflect whole body calcium status. Although the pH of urine can be altered by dietary intake, this is not true for blood pH, which is tightly regulated between a pH of 7.35-7.45.
Different parts of the body are of varying pH ranges due to their specific functions during the digestive process, as the stomach has a pH of 1-2.5, whereas the small intestine a pH of 6.6-7.5.
Some people are of the belief that milk pasteurisation (heating of milk to ensure pathogens are destroyed) decreases the nutritional value. However, pasteurisation does not result in a significant change in protein quality or other nutrient contents. Furthermore, as raw milk does not undergo the pasteurisation process, there could potentially be an increased risk of pathogen contamination.
What Are The Potential Benefits Of Dairy Consumption?
A reason often cited by individuals for the withdrawal of dairy is due to a potential inflammatory effect. Inflammation has been shown to contribute and develop such chronic diseases as cardiovascular disease, diabetes and metabolic syndrome. However, no adverse effects on low-grade systemic inflammatory biomarkers were found in overweight and obese adults who consumed dairy products . Furthermore, a review of clinical evidence found an anti-inflammatory effect for both healthy individuals and individuals with metabolic disorders.
Dairy products are considered one of the best dietary calcium sources due to their rich calcium content, high bioavailability and relatively low cost. Calcium and phosphorus play an important role within bone health, whilst additional roles of calcium include: muscle contraction, nerve conduction and blood clotting.
High Quality Protein Source
Milk protein consists of 80% casein (slower digestion/absorption) and 20% whey (faster digestion/absorption) protein. Both casein and whey are high quality protein sources due to their rich essential amino acid content. This highlights the effective role dairy products can play in stimulating muscle protein synthesis.
When on an energy restricted diet a higher calcium intake (e.g. dairy consumption) suppresses the activity of calcitrophic hormones aiding the repartitioning of energy via increased lipolysis and thermogenesis . A reduced efficiency of fat absorption has been found when calcium binds with fatty acids leading to the production of calcium soaps that increase faecal fat excretion resulting in energy loss.
Due to dairy’s high protein content ingestion of such food sources can aid the feeling of fullness and therefore influence a potential reduction in total energy intake.
Beneficial Bacteria Content
The presence of ‘good bacteria’ within yoghurt aids lactase activity, which plays a role within the digestion of lactose, whilst antimicrobial properties are also present within milk. The consumption of ‘good bacteria’ is beneficial for gastro-intestinal and immune health.
The consumption of milk can contribute to daily fluid intake. Furthermore, such consumption can aid fluid retention due to the electrolyte content, therefore aiding hydration.
Myth 4: Fasted Cardio Is Superior For Weight Loss
Fasted steady state cardio exercise is a fat loss strategy that has been utilised for many years, with its use particularly prevalent within bodybuilding and weight making sports, although such a strategy has frequently been utilised by recreational trainers looking to enhance their fat loss efforts. The rationale for fasted steady state cardio is based upon that during low intensity exercise primarily fat will be oxidised (burnt) for energy, as opposed to carbohydrate, with many people of the belief that body fat will therefore be lost. However, is this necessarily the case?
Although, training in the fasted state has shown the ability to enhance aerobic metabolic adaptations, as well as improved glucose tolerance and insulin sensitivity, I shall concentrate on whether such a strategy is a superior approach, in comparison to fed steady state cardio, for those looking to optimise body composition via increased fat loss.
Fat Oxidation and Exercise
Following an overnight fast due to the lower glycogen and insulin levels fat will be the primary energy source at rest resulting in the oxidation of mobilised fatty acids (FA) from adipose tissue via a process referred to as lipolysis. Alternatively, if an individual were to consume a meal (e.g. breakfast) prior to exercise the elevation in insulin would favour carbohydrate oxidation for fuel (glycolytic flux), therefore suppressing lipolysis. Fat is the predominate fuel for energy at low to moderate exercise intensities, with peak fat oxidation rates appearing between 45-65% V02 max. Such fat oxidation rates are dependent upon exercise intensity, duration, gender, training status and dietary intake. However, it is also important to consider the contribution of the fat source oxidised during varied exercise intensities. Adipose tissue provides the primary site of fat storage within the body via triglycerides (TG) within subcutaneous and visceral fat, whilst smaller quantities of stored TG are also found within muscle as intramuscular triglyceride (IMTG), or within the blood as lipoproteins or free fatty acids. The primary focus for individuals looking to enhance their body composition is to achieve a decrease in fat mass derived from subcutaneous and visceral fat stores i.e. adipose tissue.
24 Hour Fat Oxidation
Recent research has highlighted that steady state fasted cardio exercise has shown the ability to enhance 24 hour fat oxidation rate (how much fat is burnt for energy over 24 hours). Exercise performed after an overnight fast increased 24 hour fat oxidation via an increased transient energy deficit within both males and females, than when incorporating fed exercise following breakfast. However, it is important to note that there was no difference in 24 hour energy balance between groups, which is the key determinant of weight loss based upon the laws of thermodynamics, where a consistent energy deficit (energy intake is less than energy expenditure) is required to achieve weight loss. In fact the authors state that “the effect of a single bout of exercise on 24-h fat oxidation cannot be extrapolated to the reduction of body fat with chronic exercise”. Further research would therefore be required to investigate over a prolonged time period, whilst also incorporating body composition measures (fat mass and fat-free mass) both pre and post-intervention to inform real-world applicability. Furthermore, with no data regarding the source of fat oxidation leaves further questions as to the influence upon subcutaneous and visceral fat stores. As exercise intensity increases the contribution of fat sources will vary, as at very low intensities (25% V02 max) energy is primarily via the oxidation of plasma FA and only a small contribution from plasma TG and IMTG. However, as the intensity increases to moderate intensities (65% V02 max) IMTG energy provision increases. It is also important to consider that IMTG use is greater within trained individuals, which could provide insight as to why trained individuals have shown higher 24 hour fat oxidation rates.
Individuals with fat loss goals often become solely focused upon the source of fuel use during a narrow time period (e.g. during the exercise bout) without an appreciation of the dynamic nature of the human body and its ability to adjust substrate for fuel over the course of the day.
For example, when conducting either fed or fasted steady state cardio (65%HR max) a compensation was found for greater fat utilisation (decreased respiratory exchange ratio), as opposed to carbohydrate, later in the day (at 12 and 24 hours post-exercise) during the fed exercise condition, with the reverse true for the fasted condition. Furthermore, the consumption of nutrients pre-exercise may provide an increased thermic effect of exercise due to the elevation in post-exercise oxygen consumption, which may therefore balance out the enhanced fat oxidation rates of fasted exercise.
Fed vs. Fasted: Influence on body composition
One such study was the first study to investigate the direct effects upon body composition comparing fasted vs fed steady state aerobic exercise when utilising a planned calorie deficit. Over 4 weeks 20 healthy female volunteers were divided into a fasted steady state cardio group or a non-fasted steady state cardio group (60mins x 3 per week at 70% maximal heart rate), with all training sessions supervised and customised dietary plans created by a nutrition professional.
What did they find?
(1) Body Mass: A significant decrease in body mass from pre to post, with no significant difference between groups.
(2) BMI: A significant decrease in BMI from pre to post, with no significant difference between groups.
(3) BF% (ADP): No significant difference between groups, with a trend for decrease % pre to post.
(4) Waist Circumference: No significant difference between groups, with a trend of a decrease pre to post.
(5) Fat Mass: A significant decrease in fat mass pre to post, with no significant difference between groups.
(6) Fat-Free Mass: No significant difference between group and no significant effects of group or time.
The authors therefore concluded that there was no difference in any body composition outcome when utilising either fasted or fed steady state cardio. However, it is important to acknowledge there were limitations to this study.
Based upon the research discussed there appears to be no additional benefit regarding fat loss when implementing fasted steady state cardio over fed (non-fasted). However, there could be a small undetected benefit that can’t be ruled out and further research is required.
For individuals concerned with fat loss their focus should be upon consistently maintaining a calorie deficit (energy intake less than energy expenditure) and opting for a training method (fasted or non-fasted) which suits their personal preference and schedule.
Myth 5: Sugar Addiction
Just a quick search on google will show results of people claiming to be fighting a battle with sugar, with others proclaiming its drug like effects. In instances like this, it is always best to refer to the scientific research.
Firstly, we do not eat sugar on its own (well I hope not!). We consume foods within our diet where sugar may be included within it. Some foods with naturally occurring sugars, some may contain added sugar.
Secondly, the majority of the research upon sugar addiction is based upon rodents. Now this is good for generating hypotheses that can then be tested further in human studies. However, caution is issued with rodent findings, due to the differences between humans and animals. In certain instances, the dosage is beyond that what would be typically consumed by a human.
So why do some people feel drawn to sugar consumption? Well, its consumption activates regions within the brain that stimulate pleasure and reward. It is therefore highly palatable, with enjoyment from its consumption.
However, it is important to differentiate between something that an individual finds highly palatable and addiction. The findings of a recent review of the current scientific research states: “the science of sugar addiction at present is not compelling … and any analogies suggested based on the regulation of illicit drugs would be specious.”
Sugar consumption does not automatically result in fat (weight) gain like some people may think it does. As it is highly palatable and not satiating, it is therefore easy to over consume. It is the overconsumption of calorie intake that increases the risk of weight gain. It is important to remember that sugar is not nutrient dense and is therefore not a great dietary option for regular inclusion.
A scientific review concludes: “Given the multitude of interacting factors that increase one’s risk for eating disorders and obesity, we argue that support of sugar addiction as a primary causal mechanism of weight gain represents an extremely narrow view that fails to capture the complexity of these conditions.”