In the early 1900s, Americans were told to eat more than 100g of protein a day. As recently as the 1950s, people were encouraged to boost their protein intake. Even today, certain diet books encourage high protein intake for weight loss, although most Western diets already tend to contain twice the amount of protein needed.
Although those following high protein diets may have short-term, and even long-term success in losing weight, they are often unaware of the health risks associated with a diet too high in protein. Excess protein has been linked with osteoporosis, kidney disease, calcium stones in the urinary tract and some cancers. There are many other benefits to eating a plant-based diet.
The Essential Amino Acids
We build muscle and other body proteins from amino acids, which come from the proteins we eat in food. A varied diet of beans, lentils, whole grains and vegetables contains all the essential amino acids. Scientists once thought various plant foods had to be eaten together to get their full protein value, however, modern research suggests this is not the case.
Many nutrition experts, including the American Dietetic Association, now believe protein needs can be met simply by eating a variety of plant proteins throughout the day. However, it is important to eat enough calories to meet your energy needs.
The Dangers of Too Much Protein
The average Western diet contains meat and dairy products and as a result is often too high in protein, which can lead to a number of serious health problems including kidney disease, cancer and osteoporosis.
Kidney Disease
When people eat too much protein they take in more nitrogen than they need, which places a strain on the kidneys. The kidneys must in turn get rid of the extra nitrogen through the urine. People with kidney disease are encouraged to eat low-protein diets as this reduces excess levels of nitrogen.
Cancer
Although fat is the dietary substance most often cited for increasing cancer risk, protein also plays a part. According to a 1997 report by the World Cancer Research Fund and American Institute for Cancer Research, populations that regularly eat meat are at increased risk for colon cancer. Researchers believe that the fat, protein, natural carcinogens and absence of fibre in meat all have a role to play.
Osteoporosis and Kidney Stones
Diets rich in animal protein may cause people to excrete more calcium than normal through their kidneys and increase their risk of osteoporosis. Countries with lower protein diets have lower rates of osteoporosis and hip fractures. Greater calcium excretion also increases the risk for kidney stones.
Athletes as Vegetarians
For many years nutritionists thought athletes needed much more protein than the rest of us. In fact, athletes, even those who strength train, need only slightly more. These amounts can be easily reached by eating larger servings and increasing calorie intake by replacing animal products with whole grains, vegetables, legumes, nuts and fruits. The most important thing is to eat a variety of plant foods in a large enough quantity to maintain weight and ensure an adequate protein intake.
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