Why popular diets don't work

Oct 6, 2012 at 7:08 a.m. ET

It seems as if a day doesn’t go by when we don’t hear about something related to weight loss, diets or obesity. The latest figures from Robert Wood Johnson Foundation's Health Group and the Trust for America's Health predicts a national obesity rate of 44 percent by 2030. With so many well-known diets available today, why is it the weight of the nation seems to keep increasing?

Woman eating pea and carrot

The answer is simple: Most diets don’t work. Let’s take a look at some of the more common diets out there today, then discuss the one and only way to lose and maintain weight successfully.

For starters, most diets are not about constant improvement and a healthy way of living. Any diet that minimizes or eliminates intake of any overall type of nutrient will wreak havoc with prolonged use. Compounding the problem is that people get frustrated and start switching diets. The body becomes confused; the diets are not effective and can have serious side effects.

Protein diets

High-protein (or low-carb) diets became popular in the 1990s. Most people know of high-protein diets thanks to Dr. Robert Atkins and his world-famous Atkins Diet. These diets go by many different names, but they all follow a similar formula. They severely limit the consumption of carbohydrates, such as bread, pasta or potatoes.

Advocates of protein diets claim that a body deprived of carbs will burn excess body fat and weight loss will follow. Some of these plans allow unlimited portions of any type of meat, fish, eggs and cheese.

Weight loss is often substantial in the early period, but the lost weight is water, not fat. When a protein diet is discontinued and carbs are reintroduced, many dieters balloon back to their previous weight or higher. The rebound is not because of the carbs but because of the regain of water weight and continuing to consume excess fatty protein. If you limit vegetables, fruit and grains on a high-protein diet, you also limit nutrients and antioxidants that are crucial for life.

Vegetarian diets

Some people choose not to consume animal foods for health reasons, while others don’t partake because of their moral or ethical philosophies. A vegetarian lifestyle is an excellent way to live, and possibly the healthiest lifestyle if managed properly. However, a restrictive and improper vegetarian diet will cause significant health issues.

Possible side effects of a vegetarian diet: vitamin, mineral and various nutrient deficiencies; for pregnant women and new mothers, poor development of the fetus and inadequate milk production; liver and kidney damage; loss of muscle mass; headaches, dizziness, fatigue and nausea. External signs of a shortage of protein are dry skin and hair, weak nails and a frail overall appearance.

The brain, blood, muscles, tissues and all cells in the body require protein for metabolic activity. Without care and precise compensation to acquire the needed amino acids from acceptable protein sources or complementary sources, a vegetarian diet can cause the body to become deficient in some critical nutrients.


We hear of many fasting stories, with brides or bridesmaids trying to lose those few extra pounds as they try to fit into their dresses. Some people may think this is a smart way to diet, but fasting fails to promote weight loss because the body goes into a "self-preservation" mode and reduces the number of calories (energy) it burns. When the body is deprived of energy sources, it "anticipates" a shortage in the future and slows the metabolic rate to conserve energy. Fasting on a more regular basis causes the body to build up resistance, making weight loss even more difficult after each successive fasting session.

Fasting, or starving yourself for immediate weight loss, can have even more severe side effects that include vitamin and mineral deficiency, headaches, dizziness, fatigue, nausea, liver and kidney damage, and bad breath (not so ideal for the bride). Long-term effects can be organ damage, heart damage, muscle loss, and in severe cases, death.

High-fiber diets

Twenty to 30 grams of fiber a day is ideal, but is more a good thing? Excessive fiber in the diet can cause constipation and dehydration and hinder nutrient absorption. Bulk fillers (which are high in fiber) reduce hunger by absorbing fluids and swelling inside the stomach. This can cause obstructions in the intestinal tract, sometimes even requiring surgery. This is one diet to definitely stay away from.

SmoothieLiquid diet meals

You probably remember the commercials in the late 1980s with big-name celebrities endorsing liquid diet meals. Then In the 1990s, sales plummeted as the same celebrities who promoted the products couldn’t keep the weight off. Now liquid diet meals are enjoying a resurgence in popularity due to the potential for rapid weight loss.

Fast weight loss usually means fast regains and then some. Another issue is the quantity of nutrients supplied. Some shakes, especially those protein shakes aimed at athletes and bodybuilders, can provide 10 to 1,000 times more of some nutrients than the body needs. This sort of nutrient overconsumption can have a toxic effect on the body. The body may build up toxic levels of nutrients, leading to organ malfunction with prolonged use.

There is no consistency among manufacturers, and there are few regulations. Each meal replacement shake is different, and each contains a different mix of nutrients.

The sensible solution to successful weight loss

If you’re serious about losing and then maintaining your weight, don’t count calories. Count portion sizes instead. The palm of your hand is a built-in measuring device sized to fit the body it is attached to. The size of a serving should be equal to the surface area and the thickness of the palm (excluding fingers).

Your plate should be divided into three similar-sized portions of vegetables (usually green nutrient sources), protein (typically lean meat) and carbohydrates (typically wheat or other grains, or fruit). Each third of your plate is a palm-sized portion of each food type.

As a point of reference, these three servings will fill an 8-inch appetizer plate comfortably. To succeed in body-fat loss and weight management, the food on that plate needs to be lean, low in fat, low in calories, and quality foods in appropriately sized portions.

It is also important not to overeat. Remember, 20 minutes must pass before the stomach sends signals to the brain to acknowledge food consumption. That delay allows people who eat fast to consume too much before their brain says, "Enough." Therefore, it’s best to eat slowly and pause between bites. Put down the fork, chew and then swallow before eating more.

More diet and weight loss tips

Go back to basics with health and fitness this fall
Women vs. men: Different bodies, different vitamin requirements
Power foods that help guard your health