Nutrition is the single most important factor in achieving sustainable weight loss. While it is widely accepted that a healthy diet is the foundation for weight regulation, an abundance of conflicting information about the “perfect” approach to eating seems to leave most individuals perplexed about what their bodies really need to stay healthy. In reality, what works for some won’t necessarily work for others, because every diet requires long-term compliance from the person pursuing it.
With that said, there are some indisputable truths about nutrition which can be used to form a general framework for eating well. By reviewing these principles, you can begin to lay the groundwork for an effective lifestyle of healthy eating that allows you to control your weight over the long term. Here are a few of the most important factors to bear in mind.
A calorie is not simply a calorie. The macronutrients in our food produce nuanced but significantly different effects. In order to achieve and sustain weight loss, we must understand the roles macronutrients play in overall nutrition.
One barrier to weight loss has been the idea that high levels of fat intake contribute to obesity. While this school of thought took hold decades ago, it has since been dispelled through numerous studies. In fact, high-fat (and similarly, high-protein) diets are more effective for achieving and sustaining body fat reduction than low-fat or low-protein diets. Reducing carbohydrates, on the other hand, has shown to make favorable improvements in reduced lipogenesis, or formation of fat. The effect of carbohydrates is largely inflammatory, driven by increased insulin activity due to demand and later insulin resistance. Carbohydrates contribute more to cardiovascular disease than any other macronutrient.
To follow a healthy eating plan, one must develop some basic knowledge of portion sizes and daily recommended intake of macronutrients. Healthy portion control can be practiced by equating one cup to the size of a closed fist, a half cup to an open, cupped hand, a flat palm to 3 ounces, and one teaspoon to the size of a thumb.
In order to be effective, any diet plan requires two key elements: the subject’s compliance, and a caloric deficit. While a low-carbohydrate dietary approach will yield the most success, any diet plan can be used to achieve fat loss with compliance.
Sustainability is essential for long-term weight reduction and maintenance. When comparing four different dietary approaches (high-carbohydrate, high-carbohydrate and low-glycemic index, high protein, and high-protein and low glycemic-index), a high-protein diet was favored most among participants. Thus, not only does a high-protein approach to nutrition achieve short-term body fat reduction, but it is also likely easier to maintain over the long-term, due to its sustainability. It can also increase insulin sensitivity, which is a critical marker of health. While there has been minimal concern over the safety of a high-protein diet, research suggests that as long as a subject does not have compromised renal function, the addition of protein is not harmful.
There are many different unique approaches to healthy eating. Plans like Weight Watchers, Atkins, and the Paleo and Mediterranean diets each have their own benefits. The most important common theme in all of them is the avoidance of processed foods. Other dieting tactics, such as intermittent fasting, are also used to spur weight loss. Ultimately, the approach that is most successful is the one individuals can adhere to over a long-term basis.
Oftentimes, the perception of a diet plan being impermanent is one of the factors that sets individuals up for failure. In order for both short- and long-term results to take shape, it is important to instead change the entire way one thinks about food. When we implement small changes, such as avoiding processed foods, we begin to see the complex ways in which macronutrients affect our overall wellness. This establishes a foundation for more thoughtful eating and a longstanding commitment to making healthy choices.
Each type of macronutrient has its own unique properties with specific metabolic consequences. The consumption of carbohydrates, lipids, and proteins can be mixed appropriately to affect a low insulin level for fat loss promotion, and ultimately, to maintain healthy body composition. Here is a brief look at how each primary category of macronutrients affects body composition.
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Carbohydrates are one of the main macronutrients consumed as a source of energy. They are mainly sugar and starches that the body breaks down into glucose for energy and to feed cells. Carbohydrates can also be converted to fat for use as an energy source later.
Glucose, fructose, and galactose are the simplest form of carbohydrates. Glucose is used as a primary energy source, but factors such as the size of the sugar molecule consumed and presence of other nutrients contribute to important aspects of carbohydrate processing, including the rate at which it is processed and the elevation of blood sugar. Glycemic index, or the blood sugar level produced by a food, is determined by several factors, but generally, foods with low glycemic index are considered favorable for their ability to lessen cardiovascular disease risks, promote satiety, and increase fat oxidation. Other measures, including glycemic load and food insulin index, are also used to assess insulin response. In general, inflammatory factors parallel glycemic load and insulin sensitivity, so it is recommended that individuals maintain a food plan consisting of carbohydrates with reduced glycemic indexes, such as fibrous vegetables, to maintain a healthy body composition.
Drastically reducing carbohydrate intake is often the first step for individuals pursuing weight loss goals, and while results are consistent initially when motivation is highest, the approach is impractical over the long term. Thus, for the sake of longevity, individuals should instead restore complex carbohydrate sources while maintaining a low glycemic load, ultimately establishing their own carbohydrate intake to maintain desired body composition.
Glycemic control is important not only for weight management, but also for controlling inflammation. Grains, in particular, are considered the primary offenders leading to inflammatory conditions such as eczema, joint pain, dry skin, and fatigue. Thus, the majority of carbohydrates should come from vegetables, and perhaps limited servings of fibrous fruits. Athletes, who require more carbohydrates, could consider adding brown rice and sweet potatoes if needed.
“Lipid” is an all-encompassing term used to describe the group of molecules that includes fatty acids, glycerolipids, sterol lipids, and more. Fatty acids can be classified into saturated and unsaturated, and while each type produces its own specific response, it is most important to note that, in general, saturated fats are not the culprit in obesity – carbohydrates are. Likewise, carbohydrates, especially those with a high glycemic index, increase cardiovascular related disease most significantly.
Most sources of saturated fatty acids come from animal products, including milk, butter, cheese, and beef, but they are also found in certain plants, including coconuts and avocados. While previous dietary recommendations were built on the belief that these fats caused cardiovascular disease, this idea has since been disproven. This is not to suggest that saturated fats are healthy, but rather, that they are not the most critical element to monitor for reduced cardiovascular disease risks.
Fat intake should be approached by also considering the amount and type of carbohydrates and protein in a person’s diet. By following a low-carbohydrate approach emphasizing vegetable intake, for instance, would allow the individual to also emphasize whole food sources of omega-3 (anti-inflammatory) fats.
The absence of processed foods also aids in achieving reasonable levels of saturated fat intake. Most critically, however, it must be understood that carbohydrates play the largest role in obesity.
Fats are perhaps the most complex macronutrient, and while achieving a healthy omega-3 to omega-6 ratio is important, it is also critical to ingest fats that come from a quality source. Free-range animals are consistently much healthier than farm-raised animals, for instance.
Proteins are made up of a sequence of amino acids. There are both essential and nonessential amino acids, and an individual’s dietary protein needs change with age, exercise patterns, and coexisting pathologies. Protein quality, which is determined by the existing nitrogen balance and a mixture of nonessential amino acids consumed with essential amino acids, contributes to a person’s disease risks.
To control weight and risks of cardiovascular disease, consuming animal proteins in moderation is recommended. Again, the quality of the source is critical: wild fish and poultry are preferred over beef and pork. Leaner cuts, including range-fed or wild animals, are also healthier.
The decision to eat is not based on the mere need to survive. There are both physiological needs, which drive us to maintain a homeostatic energy state, as well as non-homeostatic influences. The latter encompass environmental cues, psychosocial desires (hedonics), and genetics.
In modern times, meals are no longer initiated by hunger; instead, they are prompted by established routines. Moreover, the “luxury of liking,” or the fulfillment of hedonic drives, often leads people to choose energy-dense but nutritionally deficient foods, which has played a significant role in the obesity epidemic.
Mealtime signals are related to satiation, or the sensation of fullness, and satiety, which is the absence of hunger between meals. The desire to take in food is largely driven by peripheral signaling performed by hormones, including insulin, leptin, and ghrelin, among others. These key hormones contribute to satiation signals in complex ways. For instance, the gastrointestinal hormone peptide responds to ingested macronutrients, which ultimately mediates satiation signals.
Also found in the gastrointestinal tract, ghrelin increases during fasting and decreases after eating, but if feeding patterns change, ghrelin levels can, too. While a higher body mass index is associated with higher ghrelin levels, lower ghrelin levels are linked to reduced appetite, even in fasting states.
In addition to hormones, processed foods may also contribute to appetite regulation. A diet with a high content of processed foods is also linked to higher inflammatory biomarker levels and is therefore best avoided. Certain macronutrients may also contribute to either an increased or decreased appetite. Thus, in terms of not only nutritional value but also of creating feelings of fullness, all calories are created equally, and different foods can trigger different brain mechanisms. By fueling the body with what it needs versus what it wants, however, people can essentially outsmart these brain responses and avoid overeating, as well as choosing nutritionally deficient foods.
Failed diets are often a result of failure to address hedonic influences. The acts of liking and wanting certain types of food tend to eventually overwhelm most dietary plans. Thus, an individualized approach to eating well is critical to success and depends entirely on the patient’s willingness to change their thinking about eating.
If there is one key piece of information individuals should understand about appetite regulation, it’s this: humans simply cannot consume food exclusively based on desire, because most of the foods to which we would be drawn are dangerous to our long-term health. One must therefore eat based on what we need, which primarily includes whole, unprocessed foods.
With so many different diet plans to choose from, many individuals are familiar with eating plans that completely eliminate entire food groups like dairy, sugars, or alcohol. What’s important to bear in mind is that, as mentioned above, processed foods, and especially carbohydrates, are the leading agents in weight gain. Restricting consumption of these foods is most beneficial not only for short- and long-term weight loss, but also for long-term health outcomes such as lowered disease risks.
Aside from processed foods, it is largely up to the individual to determine whether an entire category of food should or shouldn’t be restricted from their diet. Here, we’ll review some key considerations to help guide your decision making.
In their quest to maintain wellness, many individuals seeking a healthy eating plan wonder whether or not they should eliminate dairy from their diets. Whether or not dairy can be considered healthy depends on a number of factors. Thus, there is no definitive answer; instead, a more appropriate approach might be to develop the understanding that some forms of dairy are healthier than others. Whole milk, for instance, is high in vitamins A and D. Skim milk, however, has these nutrients removed when fat is removed. Likewise, products produced by free-range animals in a drug-free atmosphere are considered healthiest. In general, milk tends to produce an insulinogenic effect, while cheese is not because it is comprised primarily of fat and protein. Ultimately, future studies must be conducted to assess impacts of dairy products more closely.
Dairy does have some noteworthy nutritional qualities, including high levels of calcium and vitamin D. Moreover, a clear link between dairy and increased risks of cardiovascular disease and type 2 diabetes has not been established. Interestingly, patients without metabolic syndrome show reduced inflammation with dairy intake. However, because the nutritional properties in dairy can be acquired through other means, anyone who experiences an allergenic response or discomfort after consuming it should avoid it.
Dairy should be viewed as a carbohydrate rather than a protein. Select types of dairy, such as foods like cottage cheese and Greek yogurt (unsweetened and plain), can be beneficial in promoting weight management. Cheese and butter, however, should be eaten sparingly. Vitamin K can be consumed through leafy green and cruciferous vegetables, while healthy vitamin D levels can be achieved through short time frames of daily sun exposure.
As there is an array of dairy products, each fit into a macronutrient profile differently. Overall, dairy is not viewed as a carbohydrate – milk is. Cottage cheese and plain, unsweetened Greek yogurt is treated as protein and cheeses/butter are utilized as a fat source.
Additionally, to have a more comprehensive understanding of how different types of dairy affect the individual, food sensitivity and nutrient testing is recommended.
Another subject of conflicting viewpoints is alcohol. The American Heart Association recommends a daily allowance of 1-2 drinks per day for men and 1 drink for women. Moderate alcohol consumption may produce benefits such as an improved cardiovascular risk factor profile and reduced mortality. Nonetheless, alcohol consumption is also linked to elevated cancer risks. Moreover, moderate alcohol consumption can also easily turn into episodic binge drinking, and is also often socially coexistent with other harmful behaviors, such as smoking. The benefits of alcohol are easily achievable through sound nutrition and exercise.
While alcohol can have mild cardiovascular benefits with light to moderate drinking, individuals should understand that they are making an allowance for a toxin if they choose to drink. Alcohol increases number of calories consumed, so anyone pursuing weight loss goals may benefit from avoiding it.
Green tea is one of the most valuable dietary additions individuals can choose. Its properties have been shown to reduce cold and flu symptoms, protect against cognitive decline, and promote fat oxidation in both liver and muscle.
Diets high in added sugars are associated with increased markers of cardiovascular disease. Sweetened beverages, in particular, are among the worst offenders and should be avoided altogether. Natural sugars, on the other hand, such as those found in fruit, are associated with reduced risks of type 2 diabetes and cardiovascular disease. Fruits with low glycemic indexes (cherries, citrus fruits, and apples, for instance) may deliver the greatest advantage.
Any artificial sugars should be avoided in food sources, as they suggest negative health consequences. Artificial sweeteners in particular facilitate an unhealthy relationship with food by supporting an inclination towards excessively sugary tastes.
The daily recommendations of salt, like those determined for fat, are misguided. Sodium is essential to cell functionality, and following a restrictive low-salt diet will inevitably lead to a low adherence rate. For most individuals, consuming 4-6 grams of salt per day is considered healthy.
Nutrition is an integral component of weight management, but due to its inherent complexity, it must be approached with careful consideration. Despite an abundance of fad diets and an overwhelming amount of literature on weight management, obesity continues to be a global epidemic, with rates continually rising across all classes of society. It is the most preventable disease in the U.S., but left unaddressed, it is linked to elevated insulin levels, increased inflammation, and ultimately, metabolic syndrome, which leads to chronic conditions such as diabetes mellitus II and cardiovascular disease.
On a global level, more energy is being consumed than expended, but the issue of excess food intake is far more complicated than that. Factors such as the availability of processed, nutritionally poor food products and a limited understanding of the role of macronutrients, among other factors, present barriers to long-term nutrition. More importantly, nutrition is often sought after as a “quick fix” to lose weight – not necessarily maintain body fat loss – via approaches that are not sustainable. Long-term compliance and a deeper understanding of nutrition are required to maintain healthy eating habits.
Additionally, it has become too easy to be misled by conflicting or unreliable information on nutrition. To verify that a source of literature is trustworthy, individuals should seek information from controlled, unbiased studies and those that address absolute (instead of relative) risk. Then, it must also be determined that the information presented in the study is applicable to a patient’s unique circumstances.
Ultimately, although there is a shared desire to enjoy food, the reality is that we cannot simply eat what we want. In order to enjoy the other activities of life, we must eat to nourish our bodies. This includes avoiding processed foods and added sugars, maintaining a healthy balance of macronutrients, and avoiding overindulgences. By altering our mindset towards food, we can begin to enjoy what we need.
Nutrition is the single most important factor in achieving sustainable weight loss, and every diet requires long-term compliance from the person pursuing it. The complexity of nutrition requires careful consideration of not only the type of diet you are on, but the role of each component (carbohydrates, lipids, protein, sugar, sodium) being consumed.
There are additional nutrition topics to consider in your journey to weight loss. Alcohol increases number of calories consumed, so anyone pursuing weight loss goals may benefit from avoiding it. Dairy does have some noteworthy nutritional qualities, including high levels of calcium and vitamin D. Select types of dairy, such as foods like cottage cheese and Greek yogurt (unsweetened and plain), can be beneficial in promoting weight management. Green tea is one of the most valuable dietary additions individuals can choose as its properties have been shown to reduce cold and flu symptoms, protect against cognitive decline, and promote fat oxidation in both liver and muscle.
The reality is that we cannot simply eat with we want. Instead, we must eat to nourish our bodies. Avoid processed foods and added sugars, and verify that a source of literature is trustworthy should you seek information on specific nutrition components.
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This guide was produced with contributions from the following key resources:
The Cenegenics Education and Research Foundation
The Textbook of Age Management Medicine Volume 1: Mastering Healthy Aging Nutrition, Exercise and Hormone Replacement Therapy
Jeffrey Park Leake, M.D., CPT
Dr. Jeffrey Park Leake is a Partner and Director of Education at Cenegenics Elite Health specializing in age management and wellness. Having trained hundreds of physicians worldwide, Dr. Leake is also the Director of Education for the Clinical Strategies for Healthy Aging course at AMM Educational Foundation.
Todd David Greenberg, M.D., CSCS
Dr. Todd Greenberg is a practicing physician with a broad range of expertise, including wellness, exercise, sports injuries, and MRI of sports injuries. He is a Radiology Clinical Associate Professor at the University of Washington.