Are there Good and Bad foods? A Sports Perspective.
In 2012, in the count down to the London Olympics, there was considerable press coverage on its sponsorship by McDonalds, highlighting the poor message that this would give for a games that was so focused on health, youth and legacy (1). Little attention was given to the well documented fact that one of the eras top sporting stars, Usain Bolt, openly counted McDonalds as a favourite food. In his 2013 autobiography, Faster than Lightning (2), Bolt recorded that he ate an average of 100 chicken nuggets a day whilst in Beijing in 2008, a diet that adequately fuelled three world records and Olympic gold medals (3). McDonald’s nuggets are not known as a sports food, specifically the high level of fat in each nugget (~19%) makes them a poor choice ahead of a high intensity training bout or competition. Adding fat to a solid or liquid meal is known to slow gastric release, potentially lowering carbohydrate availability (4,5). However, this would have had less impact on a short sprint event and the high energy value may in fact be a benefit to a 6ft5 athlete, who might be struggling to eat enough during a busy phase of competition. Nuggets are also a good quality protein source (45% chicken breast) and the flour within the breadcrumb batter is fortified with Iron, Calcium, Niacin and Thiamin. On top of this, they are familiar; one of the first pieces of advice a performance nutritionist will give an athlete training or competing abroad is not to try any new or different foods. McDonald’s restaurants worldwide have good hygiene standards, food ingredients are easily available and the product is consistent, all very important factors when you have to travel for an important event.
The need to have a safe and familiar food when you travel to competitions abroad means that even small poorly funded teams and sports will often carry cases of specialist foods with them when they travel. One of the most commonly carried products are sports protein bars and it is easy to assume that a protein bar, specifically developed with training in mind, would be preferable to chicken nuggets for sports performance. However, when you compare the composition of the best-selling bars with a portion of chicken nuggets you may be surprised by the results. The average fat content of ten popular UK bars is 13%, with the highest being 17.4% – not that different from the nuggets and certainly not low fat, a label that requires the product to be less than 3g per 100g. All the protein bars do, as would be expected contain good amounts of protein, an average of 18g about the same as 7 chicken nuggets and also contain approximately the same amount of carbohydrate as 7.5 nuggets, very similar to a normal portion. There are clearly huge differences between a portion of nuggets and a protein bar both in taste and in way the two foods would be eaten and its possibly not a fair comparison but even these differences may have been an important influence on choice, particularly in the heat of Beijing. During the 2008 Olympics the daytime temperature averaged 25.6°C, and peaked at 35°C. Many athletes report that foods and sports drinks taste far sweeter in hot climates, can be unappealing when warm and more difficult to eat (6,7,8).
What this comparison illustrates is that there is much more to food than just the tag of good or bad, context is everything. Research has shown that we tend to judge the quality of a diet more on the foods eaten, than on the combinations of foods or how they are organised into meals (9,10,11). This may be even more the case in athletes, as fitness trainers and sports coaches are identified as the key source of nutritional information in both amateur and elite sport (12), their knowledge base has been found to be low (13,14,15,16) and they are known to have a tendency to focus advice solely on performance (9) promoting the importance of specific food groups or supplements over a balanced diet.
Nutritionists have been looking at the energy and macronutrient balance of athletes diets for a long time but it is only recently that studies have started to look at the balance of nutrient intake within the meals and snacks and the timing of how these are eaten over the day. One of the reasons why scientists started to look at dietary intake in this way was the work done by Professor Stuart Phillips from McMasters University in Canada that showed there is considerable interaction between the timing of protein rich meals and muscle hypertrophy (17) and that splitting protein intake across all meals over the day is a better way to eat. This is very different from the way most people organise their diet, with studies showing that athletes eat the majority of protein and Calories at the end of the day in one larger meal (18,19,20) and late-night snacks. Current advice to improve body composition and performance is to eat 20–40 g protein (0.25–0.40 g/kg body mass/dose) every three to four hours spread evenly throughout the day (21).
Chrono-nutrition is the study of the interaction between food intake and the body’s circadian rhythm or body clock. Circadian rhythms influence the sleep-wake cycle and regulate hormone release, appetite, digestion and body temperature. Food is a powerful zeitgeber for peripheral clocks and eating high energy foods or any food at an inappropriate time is known to disrupt circadian system organisation, leading to poor health, sleep and performance (22). In the twelfth century the medieval Jewish philosopher and doctor, Rambam suggested that to have optimum health and performance you should ‘‘Eat like a king in the morning, a prince at noon, and a peasant at dinner” and modern scientific studies are backing the importance of eating early in the day for circadian synchronicity and overall health. Eating breakfast and having a greater dominance of calorie intake earlier in the day is also independently linked with greater weight loss and better sleep quality (23,24,25,26). Gastric emptying rates and gastrointestinal mobility peak in the morning (27) and having breakfast is favourable for insulin sensitivity and glucose tolerance (28,29).
If you ask any group of people what a good breakfast would be, someone will almost certainly say porridge. Oats are undoubtably good, being a great source of both soluble and insoluble fibre and containing a wide variety of vitamins and minerals. Fibre intake in the UK population is critically low (30) with only 7.5% of the adult population having the recommended intake of 30g a day (30). Whole oats are 11% fibre, the majority of which is soluble β-Glucans (31). Dietary β-Glucans have been linked with a wide variety of benefits including lower inflammation, better blood cholesterol and triglyceride control and maintenance of blood glucose homeostasis, higher gut microflora numbers and protection of the gut lining (32). Oats are also a source of good quality protein (11-17% of dry weight) (33) and a rich source of antioxidants (34). Porridge has been shown to be more satiating than cereals, including processed oat-based cereals (35,36). This is all seems good news for avid porridge eaters but unfortunately not all porridge or porridge oats are equal and its possible to think you are being far healthier than you are.
There are three main types of porridge oats that are commonly sold; rolled oats, quick or instant oats and steel cut oats. Steel cut oats are whole grains simply sliced into pieces, are harder than rolled oats and take much longer to cook. All rolled oats are first steamed to soften the grain and then rolled flat. The difference between quick or instant oats and standard rolled oats being the time for which they are steamed and also the thickness and size of the flakes. Greater steaming and smaller flakes reduce the time taken to cook. All whole grain oats have approximately the same nutrient composition but there are differences in the way in which they are digested, steel cut or larger Irish or Scots rolled oats (jumbo oats) having considerably lower glycemic index values (GI=50-60), than the more heavily processed instant or quick cook oats (GI=70-80) (37). There are also lots of differences in the way porridge can be prepared, the oats can be cooked in water, skimmed or full fat milk and with added salt or sugar. It may also be important to be mindful of how it is eaten and with what. Adding syrup, honey, nuts, seeds, fruit or cream will radically change the Calorie and nutrient content, speed of digestion and glycemic response of the bowl.
In a BBC Good Food article – ‘Eat like an athlete’, Sir Mo Farah gave his typical breakfast as coffee and cereal and said that the cereal was “normally Frosties, as I really like them – probably a little too much” (38) and he is not alone. Footballer Wayne Rooney is on record saying that he ate Coco Pops on match days (39), Basketball’s LeBron James favours Fruity Pebbles (40) and US snowboarder Chloe Kim likes Cinnamon Grahams (41). All of these cereals are high glycaemic index and high sugar. A given 30g portion of Frosties with 125ml of semi skimmed milk contains 17g of sugar, CocoaPops 11g, Fruity Pebbles and Cinnamon Grahams 15g. The current NHS advice is to limit sugar intake to 5% of total energy intake (42) and as lots of people eat more than 30g of cereal, a big bowl could easily take up to or over the total sugar allowance for the day. Within sport low glycemic index, complex carbohydrates have been traditionally favoured before training or competition to give a slow release source of energy. However, the latest position statement from the Academy of Nutrition and Dietetics, Dietitian’s of Canada, and the American College of Sports Medicine concluded that “in the majority of studies examined, neither glycemic index nor glycemic load affected endurance performance or metabolic responses when conditions were matched for carbohydrate and energy” (43), suggesting there is no added benefit to eating complex carbohydrates around sport.
The prevalence of exercise-induced gastrointestinal symptoms in athletes has been found to be around 45% (44) and amongst elite endurance athletes may be as high as 70% (45). Nutrition has a strong influence on gastrointestinal distress and fibre, fat, protein and fructose have all been associated with greater risk (46). In individuals prone to gastrointestinal problems a low-fibre diet is recommended on the day before or even a few days before a big training day or event. In these circumstances athletes are recommended to favour processed white foods, like regular pasta, white rice and plain bagels instead of whole grain or high-fibre cereals (46). In these circumstances it maybe beneficial to favour a processed breakfast cereal, particularly if eating before training or competition and there are other advantages. Most processed breakfast cereals are fortified or enriched with both minerals and vitamins, commonly Vitamin A, Vitamin C, Vitamin D, Thiamin, Riboflavin, Vitamin B6, Folic Acid, Vitamin B12, Calcium, Iron and Zinc. Fortification is controversial and there is some evidence that added minerals and vitamins are not as effective as the ones found naturally in foods (47). However, the fortification of cereals in the UK is known to be a very important part of the nutritional adequacy of some individuals diets, contributing ~24% of the average iron intake and ~23% of the average daily vitamin D intake in adults (30). These are the same micronutrients that are commonly deficient is athletes (48).
When giving nutrition advice most medical professionals and practitioners will agree that foods should be eaten as unprocessed as possible and dietetics courses generally advice that foods bought ready made should include no more than four ingredients. There is little doubt that it is better to eat home made breaded chicken than a processed chicken nugget and I would not recommend highly processed breakfast cereals without reason but it is a fact that there are no perfect foods and even if a food could be perfect, eating it repeatedly or at the wrong time would be likely to unbalance a diet (49). The perfect diet needs to take an individuals environment, lifestyle and phenotype into account. Food should be chosen to fit with these demands and be balanced across the day. There are no good or bad foods but when making choices its worth keeping an eye on the ingredients list…. There is a chance that a fast food with 8-10 ingredients may be preferable to a specialist food with 22.
- FT 8th July 2012 https://www.ft.com/content/320dcdc4-c788-11e1-85fc-00144feab49a
- Usain Bolt and Matt Allen (2014). Faster Than Lightening: My Autobiography. Harper Books
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