So Many Diets, Which to Choose?

January usually centers around New Year’s resolutions, which often involve weight loss. This is not surprising given that 39.8% of the US population is considered overweight or obese, with the prevalence of both only expected to increase in the coming years. Weight loss resolutions are certainly a boon to gyms across the country, leading to an increase in membership, at least for a while, but while exercising is essential to good health and can help with weight loss, success really hinges on what happens in the kitchen. And this is where things can really get confusing, as there are an abundance of diets to choose from, including those focused largely on calories, such as Weight Watchers with its points system and Jenny Craig with its diet meal plans, and then those that emphasize certain macronutrients.

Regardless of which diet you choose, weight loss requires creating a calorie deficit. Generally, a deficit of 3,500 calories will result in losing 1 lb. So, even a diet consisting solely of Twinkies can result in significant weight loss if there is a sustained calorie deficit, as one nutrition professor’s experience showed in 2010. However, a diet consisting solely of Twinkies really isn’t a good idea from a sustainability and general health perspective.

Nevertheless, with an abundance of diets to choose from and a slew of new fad diets constantly being touted, how does one decide? It’s important to remember that there is no magic diet that will work for everyone and definitely no effortless way to lose weight, no matter what “miracle” someone is trying to sell you. Successful weight loss requires realistic expectations and persistence. You didn’t gain 30 lb in 1 week, so you can’t expect to lose that in 1 week either. So always be wary of diets that seem to promise the impossible.

Furthermore, we all have different genes, body types, lifestyles, health status, and environmental factors to contend with, so each of these things will need to factor into the decision-making process. If you have a lot of weight to lose or any underlying health issues, it’s really important to consult with a doctor or registered dietitian (RD) before starting any diet plan. If you have no restrictions on which type of diet you can pursue, then you have to really think about what type of diet is most realistic and sustainable for you. This requires asking yourself questions like: Can I completely eliminate processed food from my life? Can I maintain a low-carb diet? How much time can I devote to food preparation? Will I enjoy this diet?

Ultimately, you want to think about what sort of dietary changes can become a lifestyle for you, so when you reach your goal weight, you’ve established a new dietary pattern that can help you maintain what you’ve achieved. The last thing you want to do is quickly gain back all the weight you’ve worked so hard to lose.

Now, let’s look at some of the more popular macronutrient-focused diets out there to see how they work, which may help you decide on your own approach.

Atkins Diet: Limits intake of carbohydrates, particularly simple carbs (eg, starchy and sugary foods), and focuses on consumption of protein and fat. The diet is divided into 4 phases:

• Phase 1: This is the induction phase and lasts approximately 3 weeks. During this time, only 20 to 25 grams of carbs from vegetables are allowed. The goal is to get the body into a state of “ketosis,” which occurs when the body switches from burning carbs to fuel your body to burning fat.
• Phase 2: Increases the intake of complex carbs to reach a maximum of no more than 50 grams. The goal is to determine how many carbs can be consumed without hindering weight loss. During this phase, some fruit is allowed back into the diet.
• Phase 3: This phase kicks in when there are about 10 lb left to lose to achieve the goal weight. During this time, 50 to 80 grams of complex carbohydrates can be consumed daily. The goal is to slow down weight loss and work toward a diet similar to that of the maintenance phase.
• Phase 4: This is the maintenance phase, which occurs when the goal weight is achieved. During this time, the recommended carbohydrate intake is between 80 and 100 grams, provided the goal weight is maintained at this level.

Ketogenic (Keto) Diet: This is a very low-carbohydrate (≤20 net carbs daily), high-fat diet. Moderate protein consumption is allowed. The goal is to get the body into a state of ketosis, which requires a very precise balance of macronutrient ratios. Because the diet switches the body’s primary fuel supply to fat, insulin levels are drastically lowered and fat burning is increased. The diet was originally created to reduce seizures in children with epilepsy. While on this diet, some people monitor the ketone levels in their urine to ensure they are maintaining ketosis.

Paleo Diet: This diet strives to mirror the diet that was available to our paleolithic ancestors (ie, “cavemen and women”). Subsequently, the diet emphasizes consumption of nonprocessed foods, including fruits, vegetables, nuts/seeds, lean meats, seafood/fish, and eggs—basically anything that could have been obtained through hunting and gathering. This means consumption of things like grains, dairy, juices, legumes, and artificial sweeteners are to be avoided.

Mediterranean Diet:  This diet strives to mirror the traditional diets of people living by the Mediterranean Sea, including Italians, Greeks, and Croatians, before the widespread availability of processed foods. The diet emphasizes consumption of fruits and vegetables, whole grains, seafood, nuts, legumes, olive oil, and even a bit of red wine. It is considered to be particularly beneficial in promoting cardiovascular health.

South Beach Diet: The South Beach diet emphasizes consumption of high-fiber, nutrient-dense foods. While it does not require carb counting, the recommendation is to reduce overall carb intake by focusing on complex carbohydrates. Like the Atkin’s diet, there are phases, which are as follows:

• Phase 1: This is an induction phase and lasts 2 weeks. The goal is to reduce the desire for sugar and simple carbohydrates to help spur weight loss. During this time, lean proteins (meat/chicken/fish), vegetables, eggs, fat-free/low-fat dairy products, and unsaturated fatty acids (eg, olive oil) can be consumed. If weight loss is not a goal, this phase can be skipped altogether and phase 2 followed instead.
• Phase 2: This is similar to Atkins phase 2, in that some foods prohibited in phase 1 get added back into the diet. In this case, certain starchy but nutrient-dense carbohydrates can be added back in, such as whole wheat bread and brown rice. This phase is maintained until the goal weight is achieved.
• Phase 3: This is the maintenance phase. No foods are off limits but the goal is to follow the healthy eating principles that were observed during the first two phases so that the weight loss is sustained.

All of these diets have shown various health benefits, from reducing cancer risk to improving cholesterol and blood sugar levels. Some have also been associated with certain health risks, such as the keto diet, which is very restrictive and can contribute to cardiovascular problems if saturated and trans fats are overconsumed for an extended period of time. While there are definite differences between these diets, there are also some similarities, including restricting intake of carbohydrates, particularly simple carbohydrates such as starchy foods and sweets (eg, anything made with white flour or containing lots of sugar), and, expect for the keto diet, favoring nonprocessed foods that are dense in nutrients.

Importantly, you may not necessarily need to follow any particular diet to lose weight. Many people have had considerable success just changing a few bad habits, such as by cutting out soda and sweets, eating more vegetables, and adding more physical activity into their day.