Healthy Food & Healthy Living by Dr. Ayala

Why cooking helps with weight loss and wellness

There’s a clear link between eating home cooked meals and diet quality. Eating more home-cooked meals is also associated with lower risk of obesity.

Teaching cooking skills is an important method for improving eating habits, and is more effective than just instructing people about nutrition, but what kind of cooking should be emphasized in these lessons? 

The healthfulness of cooking practices depends on both ingredients and techniques. Health promoting cooking methods include using whole grains, adding herbs and spices, using healthy oils such as olive oil, incorporating fruits and vegetables, using onion and garlic, and using lower amounts of fat. On the other hand are health compromising cooking methods such as deep frying, use of processed foods, animal fat, processed meat, and adding sugar and sweeteners in cooking. A method for quantifying healthy cooking has been established – the Healthy Cooking Index applies a point for each health promoting behavior, and deducts a point for health compromising actions. 

A new study in Appetite looks at about 150 overweight or obese people undergoing a weight loss program. The participants were assessed for cooking practices after the weight loss intervention.

And the results: those who had a higher healthy cooking score achieved more weight loss and ate healthier.

Next, the researchers attempted to identify cooking patterns and came up with three types of cooking: Red Meat Simple, Vegetarian Simple, and Health and Taste Enhancing. 

Red Meat Simple cooks used fewer healthful additions, such as whole grains, fruit, and vegetables, or olive oil while using more red meat and animal fat and cooked meat to high temperatures. 

Vegetarian Simple cooks cooked less meat, were more likely to add fruit and vegetables, to cook with herbs and spices, use healthy cooking techniques (baking, boiling, or steaming), moderate salt and oil use, and to avoid deep frying and cooking meats to high temperatures or charring. 

The Health and Taste Enhancing cooking is characterized by higher use of taste enhancers including herbs,  spices and alliums, as well as healthful use of oils such as olive oil, fruits, vegetables, and whole grains. These kind of cooks were more likely to marinade meat prior to cooking, and to use low-fat cooking methods and moderate the salt and oil when cooking. 

The researchers found that The Red Meat Simple cooking pattern was associated with less weight loss compared to the other patterns.

Why would that be? Healthier cooking habits translate diet advice into everyday life, and make guidelines into meals. Eat-more-veggies is an abstract aspiration, while a tasty salad bowl is an adoptable habit.

Other studies have shown that hands-on cooking lessons resulted in weight loss compared to guidance followed by demonstration only.

The cooking patterns analysis hints at what's most important to impart in cooking classes: “complexity is not a necessary aspect of healthy cooking,” the authors write. “Having more advanced technical cooking skills and, in turn, making more complex dishes does not necessarily yield healthier food consumption. Promoting cooking practices that are likely to positively impact the nutritional content of the foods prepared and deterring the use of practices that are likely to negatively impact the nutritional content of foods we prepare may be more important than trying to achieve advanced levels of culinary expertise.”

Cooking plants 

Since what’s missing most from the American diet is plant based foods and whole foods, practicing kitchen skills on these ingredients is the most valuable.

A study looking at the veggie consumption and cooking skills of university students in Brazil found that less than half the students ate vegetables regularly, but knowing how to cook was significantly associated with eating veggies daily. These results are in agreement with another study of more than 1000 freshmen in the US that found that confidence in the ability to cook from basic ingredients and to follow a recipe was associated with eating more fruits and vegetables and better weight status. 

The basic skills we all need as cooks should include salads knowhow, what to make with whole grains, and a few basic cooking techniques that incorporate vegetables with grains and with protein sources, such as making a stir fry, cooking a soup, and oven roasting.

Knowing how to make healthy, tasty, simple and affordable meals is key to health and weight control, it’s a practice that’s central to wellbeing.

Dr. Ayala

How sustainable are the keto and paleo diets?

Food is one of the most direct ways in which we connect to nature. Even the most urban dwelling person eating a processed diet eats what comes from nature. 

Food choices also affect nature. Food production is intimately intertwined with the environment and with our climate, especially with the exponential growth of the human population and our expanding consumption patterns.

And food choices matter: Our diet affects our own health, and also the health of our planet, as the carbon footprint of different food choices carries different environmental costs. 

The American diet changes over time, and as people aspire to improve their health and weight status they’re open to hearing about new eating patterns – and their environmental impact. On the rise are the Mediterranean style diet and several plant forward ones, and the paleo and keto diet are also gaining a following – it’s estimated that ~10 percent of Americans are giving them a try. A new study in the American Journal of Clinical Nutrition looks at the carbon footprint of these and other popular diets.

The study includes more than 16,000 people whose diet was categorized into vegan, vegetarian, pescatarian, paleo, keto, or omnivore – which includes all other diets. The carbon footprint of each dietary pattern was calculated using a previously developed database of food impacts on the environment called dataFIELD. The diet quality of each diet was assessed by comparing it to the Healthy Eating Index (HEI) and the Alternate Healthy Eating Index (AHEI). 

And the results: Keto and paleo diets have a higher carbon footprint and a lower mean diet quality than vegetarian, vegan, and pescatarian diets. The keto diet, which is a high-fat low-carb diet, is estimated to produce almost 3 kg of carbon dioxide for every 1,000 calories of food. The paleo diet, which prioritizes meats, nuts and vegetables, emits 2.6 kg of carbon dioxide for every 1,000 calories. A vegan diet, on the other hand,  generates 0.7 kg of carbon dioxide per 1,000 calories – less than a fourth of a keto diet.

How much difference could changing your diet make? “For any given day, if a third of the omnivores consumed a 2000 kcal vegetarian diet, and assuming accompanying shifts in domestic production, the savings would be equivalent to eliminating 340 million passenger vehicle miles,” the authors write. Over a year this would amount to about 5 percent of what we needed to do to meet the US targets of the Paris accords, and improve our diet quality, reducing risk of chronic disease.

An omnivore’s compromise

The single most environmentally-impactful food choice regards animal products. Animal food production emits much more greenhouse gasses than plant foods. Beef production emits 10 times more than chicken, and 20 times as much as growing legumes, nuts and seeds. 

Studies show that vegan and vegetarian diets emit less greenhouse gasses. Several other diets that are usually adopted for health benefits – such as the Mediterranean-style diet and the DASH diet also carry a smaller carbon footprint than the typical American diet.

We can all take steps towards greater sustainability by eating more plants and less meat, eating less processed foods, choosing organic when possible, preferring produce that's locally grown and in season, and avoiding waste.

Even the smallest steps count in a world with more eight billion people making food choices.

Dr. Ayala

Is soda bad for your brain?

One of the biggest fears we face – especially if we’re lucky enough to live a long life – is dementia. Despite great efforts to treat Alzheimer's and other dementia forms, there is no cure for this malady. Prevention is crucial.

Important modifiable risk factors for dementia are poor nutrition, binge drinking, lack of physical activity and mental stimulation and smoking.

A new study in the American Journal of Clinical Nutrition looks at a large population of almost 180,000 people in England, with no signs of dementia at the start of the study, and follows them for an average of almost 10 years. The diet of the participants was reported, and their sugary drink consumption tallied. The genetic risk of dementia was assessed for each participant looking at common genetic variants related to the risk of Alzheimer’s disease. 

During follow-up almost 1300 of the participants developed dementia. After adjusting for socioeconomic status, lifestyle factors, such as alcohol intake, smoking, exercise and weight status, and underlying health conditions that may affect dementia risk, the researchers found that those who consumed more than 2 sugary drinks a day had greater odds of developing dementia: their risk rose by some 35 percent. Excessive intake of added sugar was also linked with dementia risk.

The added risk was seen with sugary drinks, but also with artificially sweetened ones. On the other hand, those consuming moderate amounts of fruit juices did not have a higher risk of dementia. These links were not modified by genetic predisposition.

A similar study of almost 3000 people over the age of 60 years showed almost doubling of dementia risk among those with high intake of artificially sweetened drinks, and another study of 1865 people showed greatly increased risk of dementia with an intake of on average 7 sugary drinks a week.

How could sugary drinks impair the brain? It might be that the excessive sugar and rapid rise in insulin impair the brian, and for artificially sweetened drinks the authors suggest that aspartame could disrupt energy production and increase oxidative stress.

Why are sugary drinks singled out?

The western diet contains plenty of added sugar, but while sugar’s added to many foods, most of the added sugar hides in drinks – soda, sports drinks, energy drinks, flavored milks and fruit juices – the sheer amount of sugar in sugary drinks can explain why they are linked so tightly with obesity.

But studies show that there is something distinctive about getting calories in liquid form. Solid sugars suppress hunger somewhat, while liquid sugar – in sugary drinks – doesn’t affect satiety.  Sugary drinks’ calories are just added, and the meals eaten with them will be just as large, if not larger. And several studies have suggested that sugary drinks are an independent risk factor for diabetes and hypertension irrespective of obesity. 

Liquid sugar lends itself to overconsumption, and it might very well be that sugar in liquid form poses an especially tough burden on our body’s metabolism and on our brain’s function.

Dr. Ayala 

Can your diet affect skin appearance and aging?

Healthier diets are associated with fewer face wrinkles, while a diet rich in junk food and meat with earlier skin aging according to population studies. Yes, this is just a link. It might be that healthy eaters avoid the sun and protect their skin from it – excessive sun exposure ages the skin. Health conscious people also tend to avoid smoking, another known skin-aging factor.

Does food affect facial wrinkles?

A pilot study conducted at the UC Davis Dermatology Clinic that actually tests the effects of foods in a controlled setting does so with almonds. Participants (28 postmenopausal women with fair skin that tends to burn and freckle in the sun) were treated with 2 ounces of almonds daily for 16 weeks, and skin assessment was done using high resolution photos, and a computer based validated facial modeling measurement.

The almond group had decreased wrinkles after 16 weeks.

This prospective randomized pilot study was extended and expanded to 24 weeks. This time about 50 women completed the study.

The second study showed that at 24 weeks there was continued reduction of observed wrinkles, there was also reduced pigment intensity in the almond group, compared to the control (pigmentation is another sign of skin aging).

What is it in almonds that can affect the skin? Almonds are rich in vitamin E, an antioxidant that protects from ultraviolet rays that age the skin (UVA). Many nutrients affect skin health: antioxidants and carotenoids such as beta carotene prevent collagen degradation, and provide protection from ultraviolet radiation on the cellular level.

And although this study was performed with almonds, there’s likely nothing unique about these nuts: many healthy foods contain beneficial antioxidants that may reduce wrinkles and improve skin’s appearance. 

A prospective study feeding women 85 grams (~3 ounces) of mango daily for 16 weeks showed a reduction in wrinkling when assessed by photographs. Interestingly, consuming 250 grams (~9 ounces) of mango daily increased wrinkles after 16 weeks. The researches suggest that this unexpected result may be due to the high sugar intake associated with eating high amounts of mango.

Eat well for rosy, clear skin

A skin change that’s clearly connected with food is its pigmentation. 

Skin’s pigment changes after sun exposure: most of us tan when exposed to the sun, by the production of melanin. Skin’s color also changes by the pigments we ingest, mainly due to carotenoids found in carrots, sweet potatoes, dark green leafy greens, sweet red peppers and other colorful fruits and veggies. 

The skin tone associated with eating a carotene-rich diet is deemed more attractive and vibrant in experimental studies.

A study following 35 students for 6 weeks looked at how fruit and veggie intake affects skin tone, as measured by a spectrophotometer. The researchers found that measured skin tone correlated with reported changes in the diet: eating more fruits and veggies increased skin redness and yellowness, and these skin tone changes were achieved with about 4 servings of fruits and veggies.

What we eat, unsurprisingly, affects our wellbeing, and several skin disorders can also benefit from improving the diet. Take acne, one of the most common skin complaints, with 80-90 percent of US teens with some degree of acne. Recent research connects the Western diet – high in processed foods, sugars and animal products, low in plant and whole foods – with acne prevalence and severity.

There are countless reasons to eat more fruits, vegetables and nuts, but if you need yet another compelling one: Good food may give you beauty from within, and is probably at least as effective as some of the expensive creams in the market that promise to do so.

Dr. Ayala

Does when and how you exercise affect your appetite?

Exercise is a cornerstone of wellness, and is independently important. Exercise is also used as a tool to control weight, but it isn’t a very effective weight loss plan when applied without a weight-loss diet. Exercise’s less than expected influence on weight loss is attributed to our body’s tendency to compensate for energy loss by increasing appetite and intake, or energy conservation and a reduction in energy expenditure. But although exercise by itself (without calorie control) doesn’t result in significant weight loss, regular exercise is linked with lower risk of gaining weight over the years. 

Does when you exercise matter?

Does the timing of exercise matter? The study of our circadian rhythm – our internal clocks that run a ~24 hour cycle related to the sun’s activity – is showing that many of our processes, including hormonal secretion, appetite, and metabolic pathways, fluctuate with the time of day. 

A new study in the current issue of the journal Appetite looks at the effect of morning vs. evening exercise on appetite, food intake and voluntary performance.

The healthy volunteers undertook two trials, in one they exercised at 10:30 am, and in the other at 10:30 pm. They ate a standardized meal 2 hours before exercise (intense cycling), and were offered a meal after exercise in which they could eat as much as they wished.

And the results: Although the participants reported similar appetite regardless of the time of day they exercised, they ate on average 150 calories more when they exercised in the evening.

This is a small study, and bear in mind that many people, especially in the US and in Europe, tend to eat more food in the evening as it is. Also, when to exercise isn’t necessarily a choice – time constraints arise throughout the day, and it’s hard enough to fit exercise as it is.

If you do have the flexibility you can experiment with timing your exercise and seeing if it helps you better control your appetite and intake. 

High or low intensity

Another method that could supposedly help with appetite control through exercise is increasing the intensity of the workout. High intensity exercise may suppress hunger more than low intensity exercise.

High intensity interval training – short intermissions of high effort sprints, interspersed with recovery periods – is rising in popularity and is sold as a time-saving and more efficient way to train than moderate intensity continuous exercise.

A new review study in Appetite collected 13 randomized controlled studies compares high and medium intensity exercise.

The researchers found that both types of exercise suppressed appetite for a period of about ½- 1½  hours, high intensity exercise to a greater extent. Which makes sense: during times of acute exercise the body diverts its resources to muscles, and puts the digestive system on hold. We also know that appetite hormones like ghrelin are suppressed during exercise.

The diminished appetite does not last however. Hunger bounces back and the post-exercise disinterest in food is short lived, regardless of exercise intensity.

The habit you can keep

The most important thing is to exercise – time and type of exercise matter less – and even if there’s no effect on weight whatsoever.

The best exercise is the one you can do, the activity that you enjoy, that’s accessible to you, that fits your schedule, that doesn’t cause you discomfort, the one that doesn’t require equipment you don’t readily have or an ill-afforded membership. 

If you still haven’t mastered an exercise habit the most important parameter is sustainability – pick a plan that you could keep and adopt as second nature, one that you can stick to.

To an active and healthy 2023!

Dr. Ayala