Fish and other seafood are rich in proteins but low on fat.
One of their prime features is that seafood is an exquisite source of polyunsaturated fatty acid named omega 3 fatty acids.
These are healthy fats.
They are not generated by the body but are essential to body’s functioning.
Two omega-3 fatty acids found in fish are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Despite of presence of fish oil supplements in the market, it is best to consume fresh or canned fish to obtain omega 3 fatty acids and other nutrients.
Fish are also rich in iodine, selenium, calcium, phosphorous and other minerals.
It is a great source of Vitamin D. A fish diet can aid in improving hearth health, reduce inflammation and decrease the risk of brain diseases.
How fish helps in weight loss?
Fish is a high protein source. High protein diets are known to influence energy intake and utilisation. They also promote post meal satisfaction and reduce further calorie intake.
A research study was designed to observe whether fish consumption can enhance weight loss and thereby improve blood glucose, cholesterol and other related parameters.
Subjects were randomly assigned to the following groups: daily fish meal, weight loss regimen, combination of both and control.
Weight decreased by about 5 kg.
Fish alone did not improve glucose or insulin levels but the combination group brought a significant improvement in all metabolic parameters.
It was concluded that incorporating daily fish in weight loss regimen can help with weight loss and reduce risk of cardiovascular diseases.
Effect of seafood consumption on leptin and ghrelin concentrations has been studied. Leptin and ghrelin are hormones which promote satiety and control appetite.
They are also involved in fat deposition. Seafood involved in this study was cod and salmon. Control diet was void of seafood.
It was observed that seafood consumption did influence insulin, leptin and ghrelin hormones. These effects were partially gender specific and influencing these hormones can mediate weight loss.
Scientific evidence regarding fish & weight loss
We discuss here various types of fish and how they benefit in weightloss
1. Salmon for weight loss
Salmon is a fish native to North Atlantic Ocean and Pacific Ocean. It is an oily fish and is rich in proteins, omega 3 fatty acids and Vitamin D.
A research experiment was conducted to determine how seafood affects weight loss and inflammation in overweight and obese individuals.
Subjects were given low calorie diets which contained either salmon or cod or fish oil capsules. The control group received sunflower oil capsules.
Weight lost was around 5 kg and a significant decrease in inflammation was observed in all groups. However salmon was the most effective in decreasing inflammation parameters.
What does it mean? Salmon can aid in weight loss and also help in reducing inflammation.
2. Cod for weight loss
Cod is a popular food item. It is a white flesh fish. Cod liver is used to process cod liver oil which is rich in vitamins and omega 3 fatty acids.
University of Iceland conducted a study to investigate whether cod consumption can help in weight loss and improve cardiovascular risk factors.
Subjects received 150 g cod 3 times a week or 5 times a week. Control group received no seafood.
At the end of 8 weeks decrease in body weight and waist circumference was observed along with an improvement in cardiovascular risk factors.
The risk of developing metabolic syndrome dropped from 29 to 21%.
Subjects consuming 150 g cod 5 times a week lost 1.7kg more than control group. Results of the study indicated that cod consumption aids in weight loss in a dose dependant manner.
Consumption of omega 3 fatty acids is said to improve antioxidant status. In the study four low calorie diets were provided: no fish diet, cod based diet, salmon based diet and omega 3 fatty acids supplemented diet.
Weight loss was observed with sea food based diet. The study proposed that consumption of a moderate calorie diet inclusive of cod can not only help with weight loss but also improve antioxidant status.
What does this mean? Cod helps with weight loss. It also improves body’s antioxidant status and reduces cardiovascular risk factors.
3. Scallop for weight loss
Scallops are type of calms that are highly nutritious and their flavour is cherished worldwide. Scallop meat is enclosed between the shells. It is rich in vitamin B12 and other minerals.
Research was conducted on mice to examine whether proteins from different sources can help in preventing diet induced obesity. Chicken, cod, scallop and crab were the protein sources that were put to test.
Energy intake was lower in crab and scallop fed mice compared to chicken and cod but only scallop fed mice gained less weight and fat. Improvement in cholesterol and blood lipid levels was observed.
Researchers concluded that scallop protein completely prevents weight gain from a high fat and high cholesterol diet and also helps in maintaining lean mass.
What does this mean? Scallops are best choice among seafood for weight loss.
Comparison between fish types and their effect on weight loss
In this section we will go through comparative studies between various fish types and their individual outcomes in terms of weight loss.
A clinical trial investigated the effect of consumption of lean or oily fish and fish oil on blood lipid (fat) in overweight individuals.
Experimental groups received either cod or salmon or fish oil capsules along with calorie restricted diet while control group received sunflower oil.
Blood lipid levels reduced in all experimental groups. However reduction was highest in fish groups. Results indicated that weight lost diet inclusive of oily fish can also help in improving blood lipid levels.
In a clinical trial testing weight loss diets including fish, lean fish (cod) ,fatty fish (salmon) and fish oil capsules were put to test.
It was observed that inclusion of any of the three experimental foods led to a weight loss of 1 kg more than that observed by a control diet with no seafood.
What does this mean? All fish types aid in weight loss; this property is not specific to any particular species.
Comparison between seafood & other meats as high protein source
Research studies have been carried out to examine whether fish as a protein source is better than other animal protein sources.
A comparative study was organized to evaluate whether fish protein or beef protein has a greater effect on satiety. Subjects were provided with beef protein dish or fish protein dish at lunch and their subsequent energy intake was observed.
After consuming fish, ratings for satiety were high and those for hunger and desire to eat later in the day were low. Also the energy intake of subjects consuming fish protein for lunch was lower during evening meals.
Red meat is apparently said to be more filling as a meal rather than white meat. However it has been proven that among fish, beef and chicken consumption of fish leads to highest meal satiety.
Consumption of fish influenced serotonin levels (chemical produced by the brain that influences appetite and satiety).
Also it was observed that digesting a meal containing fish takes a longer time. This further reduces appetite and subsequent energy intake.
Low carbohydrate diets are said to promote weight loss. A study was conducted to evaluate whether the type of meat in a low carbohydrate diet can affect its outcome.
A comparison between a diet containing red meat and a diet containing poultry, fish and shellfish was made.
Both diets caused a significant weight loss (5.2 – 5.6 kg). The poultry, fish and shellfish diet caused an increase intake of polyunsaturated fatty acids and cholesterol but it did not affect overall blood lipid levels.
To observe whether different dietary protein sources influence how energy is utilised, obesity prone mice were fed a high fat diet supplemented either with casein, chicken or a mixture of cod and scallop as a protein source.
It was found that cod and scallop mixture prevented diet induced obesity and fat tissue deposition.
What does this mean? Fish consumption causes higher satiety ratings than any other animal protein. Consuming fish can help you lose weight without being susceptible to heart problems that are commonly posed by certain meat types.
Fish oil for weight loss
Fish oil is derived from oily fish (oily fish have oil in their tissues and in the belly cavity around the gut.)
They contain omega 3 fatty acids (EPA & DHA). Fish oil contains antioxidants. It is known to be therapeutic in treating heart disease, depression, anxiety and cancer.
Regular exercise and consumption of fish oil can help in weight loss and improve heart health. A study focussed on this idea made use of tuna fish oil and exercise in the form of walking.
Both fish oil and exercise independently caused reduction in body fat. Fish oil supplementation improved cholesterol and other related parameters.
It was proposed that consumption of fish oil supplement along with exercise can improve weight loss outcomes.
Interesting enough, high dose fish oil capsules help in weight gain in patients suffering from pancreatic cancer. Patients in the study experienced significant weight gain after 3 weeks of regular consumption of fish oil.
Dietary intake increased and improvement in performance and appetite was seen at 3 weeks. Results proved that EPA enriched supplements can help in weight gain during advanced pancreatic cancer.
What does it mean? Fish oil supplements can promote weight loss when combined with low calorie diet and exercise. It can also help with weight gain in patients suffering from advanced stages of diseases.
Other advantages of eating fish
Apart from helping with weight loss, seafood consumption has added benefits such as:
- Omega 3 fatty acids present in seafood can help reduce blood pressure.
- N-3 Polyunsaturated fatty acids in fish oil can help reduce non alcoholic fatty liver disease.
- Seafood consumption influences insulin resistance positively.
- Nutrients found in fish help to keep brain and heart healthy.
Moderate fish intake should be observed, as fish may be contaminated by toxins such as mercury and lead or pesticides.
Pregnant and breast-feeding women should exercise caution while selecting species of fishes for consumption.
Also it is important to note that cooking styles also affect nutritional value of fish. Deep fried fish or fish served with excess fats may not help in weight loss purpose at all.
Fish consumption can aid in achieving your weight loss goal.
However fish should replace equal calories in your diet and adding exercise to your weight loss regime can improve outcomes.
Omega 3 fatty acids and other nutrients present in fish and seafood are vital for the body’s overall functioning and development. One can also reap health benefits by consuming fish oil supplements but it is highly recommended to consume fresh sources of fish oil.
It is recommended to limit seafood servings to two servings/ week so as to avoid the possible risk of accumulating harmful toxins.
But to attain your weight loss goal it is best to consult a dietician or nutritionist about serving size of fish to suit your body.