Low-protein diet
The daily requirement for humans to remain in nitrogen balance is relatively small. The median human adult requirement for good quality protein is approximately 0.65 gram per kilogram body weight per day and the 97.5 percentile is 0.83 grams per kilogram body weight per day. Children require more protein, depending on the growth phase. A 70 kg adult human who was in the middle of the range would require approximately 45 grams of protein per day to be in nitrogen balance. This would represent less than 10% of kilocalories in a notional 2,200 kilocalorie ration. William Cumming Rose and his team studied the essential amino acids, helping to define minimum amounts needed for normal health. For adults, the recommended minimum amounts of each essential amino acid varies from 4 to 39 milligrams per kilogram of body weight per day. To be of good quality, protein only needs to come from a wide variety of foods; there is neither a need to mix animal and plant food together nor a need to complement specific plant foods, such as rice and beans. The notion that such specific combinations of plant protein need to be made to give good quality protein stems from the book "Diet for a Small Planet". Plant protein is often described as incomplete, suggesting that they lack one or more of the essential amino acids. Apart from rare examples, such as Taro, each plant provides an amount of all the essential amino acids. However, the relative abundance of the essential amino acids is more variable in plants than that found in animals, which tend to be very similar in essential amino acid abundance, and this has led to the misconception that plant proteins are deficient in some way.
Fish oil
In a 2009 letter on a pending revision to the Dietary Guidelines for Americans, the American Heart Association recommended 250–500 mg/day of EPA and DHA. The Guidelines were revised again for 2015-2020; included is a recommendation that adults consume at least eight ounces of a variety of types of fish per week, equating to at least 250 mg/day of EPA + DHA. The Food and Drug Administration recommends not exceeding 3 grams per day of EPA + DHA from all sources, with no more than 2 grams per day from dietary supplements.