Tuna as part of a bodybuilder's diet
High protein diets have been postulated to reduce body fat distribution by increasing fat-free mass at the expense of fat mass through higher metabolic and energy demands. In comparison to sumo wrestlers, aesthetics is just as important as the strength in bodybuilding and this can be achieved and maintained through diet and a good workout regime.
Diets which favour a high-protein intake of 1.4-2.4g/kg per day (refer to Positive Nitrogen Balance) is beneficial in maximising gains in lean mass. It is important to ensure that the absolute daily intake of protein is met, and not proportionally reduced especially during “cutting” phases which favour negative-energy diets.
Where the tuna fits
Tuna has become increasingly popular in a bodybuilder’s diet especially in Australia where approximately 31,000 tonnes of canned tuna is consumed annually. This reflects that tuna is a widely available, convenient and affordable food product which also provides health benefits from a nutritional standpoint.
The nutritional profile of tuna varies depending on the species but generally has a high protein (94%) to fat (6%) ratio with little or no carbohydrates (refer to Appendix, A). Apart from being a valuable protein source, the American Heart Association recommends consuming at least 2 servings of fish weekly to promote and maintain good cardiovascular health. Fish has a rich content of essential omega-3 polyunsaturated fatty acids, eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) that is often inadequate in our Western diet due to the significant imbalance in the ratio of omega-6 to omega-3 of 20:1 nowadays, compared to the recommended 2:1. As 100g of tuna contains approximately 280mg of omega-3s, regular consumption can help bolster our intake of omega-3s. It is recommended that 1-2g of omega-3 is consumed daily to obtain the health benefits.
Caveat -Mercury Risk ?
Although tuna may seem like a miracle food, there is definitely a certain catch to it. There is an ongoing concern regarding the inevitable risk of being exposed to heavy metals in our natural food chain especially from seafood products. Predictors of heavy metal exposure in the diet would depend on the type, size and lifespan of the fish. Larger fish which are often predators such as tuna and shark tend to accumulate more heavy metals over their lifespan. Oily fish such as salmon, king mackerel and swordfish are also found to have high mercury content.
Mercury is often quantified in parts per billion (ppb) and the alert level for the FDA is set at set at 1000 ppb for a certain food product. The US Environmental Protection Agency has determined safety limits or the Reference Dose of 0.1g methylmercury/kg body weight/day.
When choosing tuna products, you will notice the label being “light” or “white/albacore”. Light does not refer so much to the fat content but rather to the species of tuna, often skipjack species, which has higher sustainability due to its shorter lifespan. Studies have shown that 100g of light tuna have lower mercury content (approx 52 ppb) compared to white/albacore products (227 ppb). Furthermore, tuna in oil has been found to contain 3 times the amount of mercury compared to water/brine.
As such, excessive consumption of tuna products should be avoided on the long term to minimise toxicity from mercury and other heavy metals.
Moderation is Key
With moderation, tuna is undoubtedly a valuable food in a bodybuilder’s diet and should be consumed as part of a diet also including other sources of omega-3s (fish oil supplements, flaxseed etc).
It is best to consume water/brine products over oil. Tuna in brine often contains more sodium thus more flavour and should be avoided if a low-sodium diet is indicated (often for people diagnosed with hypertension or heart disease).
As tuna is rich in protein, it is a great addition to salads if on a low-carb diet whilst sandwiches or wraps provides additional carbohydrates to provide a balanced meal. When preparing meals, adding herbs (e.g. dill, thyme), citrus (lemon/orange juice) are great ways to improve the flavour.